How to create notifications in flask?

Question

Flask

I want to create a chat bot on the VKontakte callback api that receives messages from the user and sends him what he sent every month. I want to motivate myself this way. But I ran into how to implement this in flask. After all, you need to call some process through flask that will go through the database every time, select messages that were last sent a month ago and pass this selection to the function that will send them. Help me please! Thanks for all