Searching for booking script w availability included

Probably worst headline ever. Sorry.

Client is a restaurant with 150 seats. They’re offering a buffé at a fixed price. Nothing else.
I’m looking for a script where guests would be able to book seats, and that shows how many seats remains. I.e. when it’s fully booked, it shoudl say so.
The perfect script would also allow guests to pay online in advance when they’re booking.
Preferrably php/MySQL.

Anyone?