server script - something like shell

I know im probably not in the right subforum but:
I wish to make a server side script that will run every minute, manipulating the database. Is that possible?
If yes, what would a basic program look like and how would it be called every minute? (All I need is the script to compare 2 datetimes and if the difference is bigger than 5 minutes that entry would be removed from the DB)
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