Restricting access to ex4 via MySQL database

Good day

I am looking for a way on how I can restrict access to my ex4 file, by having a mysql database create an access code on a monthly basis?

It will be based on a subscription basis so once the script query my database,it will check if the subscription is active or not.

I am using PHP script on my server which can create the access codes for active members.

Thanking you in regards