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Best way to constantly check for scheduled events on a website

So I am making a website, and something that required for part of the security is having a waiting period when trying to do something, for example trying to delete something, this would help incase someone's account was stolen and someone tried to ruin their account.
I'm already using SQLite so I'm going to create a table in there where scheduled events will be defined.
What I'm wondering is what is the best way to constantly check these scheduled events, it may also be important to note I want to check at least every hour. My immediate thought was creating a separate thread and running a function on there with a while loop in it which will constantly run a chunk of code with a time.sleep(3600) at the end of the function, like this:
def check_events(self):
while True:
# code
time.sleep(3600)
I'm not sure though if this is the most efficient way of doing it.
That function currently is inside my website code class hence the self, is that something I need to put on the outside or no?

I would either create a cron job on your server (which is the most straightforward)
or use a schedule module to schedule your task, see example:
import time
import schedule
from sharepoint_cleaner import main as cleaner
from sharepoint_uploader import main as uploader
from transfer_statistics import main as transfer_stats
schedule.every(1).hours.do(uploader)
schedule.every(1).hours.do(transfer_stats)
schedule.every().sunday.do(cleaner)
while True:
schedule.run_pending()
time.sleep(10)
https://github.com/ansys/automatic-installer/blob/4d59573f8623c838aadfd49c312eeaca964c6601/sharepoint/scheduler.py#L3

How to run a function at a certain UTC time?

I'm writing a small script that starts a function at a certain time (16:00 for example), the problem is that my script obviously works based on the time of the computer, but I need it to use UTC, so that it can be used regardless of where a person lives.
I have found several libraries that do the job, but given my inexperience I can't seem to match things up ...
Here is an example of how the script works. I need to do the same thing but with UTC time.
import schedule
import time
def job():
print("make some stuff....")
schedule.every().day.at("16:00:00").do(job)
while True:
schedule.run_pending()
time.sleep(1)

Loop reddit bot to check for answers every 10 minutes

I'm making a Reddit bot that goes through comments on certain subreddits and replies to those with certain keyphrases.
I originally did not have a loop, and it worked fine, but I had to click run again every few minutes. I am running my python script on pythonanywhere.com, using PRAW.
import praw
import time
SECONDS_PER_MIN = 60
subreddit = reddit.subreddit('memes+dankmemes+comics+funny+pics')
keyphrase = ('Sauce+Sauce?')
def main():
while True:
for comment in subreddit.stream.comments():
if keyphrase in comment.body:
comment.reply('[Here.](https://www.youtube.com/watch?v=dQw4w9WgXcQ)\n\nI am a bot and this action was performed automatically. Learn more at [https://saucebot.com/](https://www.youtube.com/watch?v=dQw4w9WgXcQ)')
print('Posted!')
time.sleep(SECONDS_PER_MIN * 11)
if __name__ == '__main__':
main()
I expect it to respond to a random person who says "sauce" every 10 minutes, but now it won't respond to anyone.

Are you running your script on a PC? You could potentially use the task scheduler for that without using python at all. Just save your script as a binary using pyinstaller, then schedule it to run every ten minutes.

Is there any Python module available which can alarm after certain time

There is a significant difference between my question and the given one. If I implement sleep as given on the link (which some people think my question is a duplicate of another one) then my whole app will hang for certain time. On the other hand I am looking for a scheduler so that my app will not hang but just after a certain period of time a .wav file will run. Meanwhile I would be able to do anything using my app. Hope that makes sense.
I am going to build an alarm clock. I think I can do this according to this Algorithm...
take current time using time.clock()
compare current time with the given time.
if current time is not given time then continue taking current time and compare whether current time is the given time or not.
if current time is the given time then play the .wav file.
The problem with this program is it will continuously run until the given time. So I am looking for better idea. Let's say if there is any Python module/class/function which can play a sound file on a given time. Is there any Python module/class/function which can wake up on a given time? Or my algorithm is used usually for all alarm clocks?

As far as I know there is not a good Python module to do this. What you are looking for though is a cron job. It allows you to schedule specific scripts to run at certain times. So your Python script would end up just being the code to play the .wav, and then you would need to create a cron job to tell your computer to execute that script at a certain time each day.

Have a look at the sched module.
Here's an example on how to use it:
import sched, time, datetime
def print_time():
print("The time is now: {}".format(datetime.datetime.now()))
# Run 10 seconds from now
when = time.time() + 10
# Create the scheduler
s = sched.scheduler(time.time)
s.enterabs(when, 1, print_time)
# Run the scheduler
print_time()
print("Executing s.run()")
s.run()
print("s.run() exited")
The time is now: 2015-06-04 11:52:11.510234
Executing s.run()
The time is now: 2015-06-04 11:52:21.512534
s.run() exited

Writing a Python script that runs everyday till a specified date

I want to schedule a job (run a python script) everyday at a specific time till a specific date has been reached.
Researching on a lot of Pythonic schedulers, I thought that APScheduler was a good candidate to get around this.
This is an example snippet using APScheduler that starts a job and executes it every two hours after a specified date.
from datetime import datetime
from apscheduler.scheduler import Scheduler
# Start the scheduler
sched = Scheduler()
sched.start()
def job_function():
print "Hello World"
# Schedule job_function to be called every two hours
sched.add_interval_job(job_function, hours=2)
# The same as before, but start after a certain time point
sched.add_interval_job(job_function, hours=2, start_date='2010-10-10 09:30')
How to achieve the same and have a upper limit date after which the job should not be executed?
Any suggestions that revolve within and outside the APScheduler are most welcome.
Thanks in advance.

Use a cron job that executes your script every two hours (cron is made specifically for things like this). In your script, you just look up the system date and check, if it's smaller than your given date. If it's smaller, you execute the rest of your script, otherwise you quit.
You may also write additional code, so you get notified when the script is not actually executed anymore.

I eventually found the interval trigger can take an end_date.
You can pass arguments for the trigger to add_job with trigger='interval':
sched.add_job(job_function, trigger='interval', hours=2, end_date='2016-10-10 09:30')
I think you may be using an older version of the software.