Q:

Check if current date is between 2 dates in MySQL

I have a contract table in my database and those contracts have a start date and an end date. How can I change their active state if the current date is after the end date?
I already figured out that I'll do it with a stored procedure that gets executed every day or something like that. My Problem is, I don't know, how I can check each row in the table. It seems like something extremely basic yet I can't think of any solution.
I found this Response and it looks very promising but I'm afraid I don't understand the way it's supposed to work. 
I'd highly appreciate any and all pointers.
EDIT: I found the solution and my way of approaching the problem was way off.

A:

Thanks to @RiggsFolly I found the solution: 
UPDATE contract_conclusion SET is_active=0 WHERE CURDATE() > date_end_contract_conclusion;

