I installed a "drawer lock" on one of my cabinet doors.  You just have to
drill a hole, I think 3/4", or maybe 1", and it has a lever that turns by a
key and locks the door closed.  It's the type of lock that is on file
cabinets.

Put a piece of masking tape over the spot before you drill the hole.  I
didn't (I was lazy) and the laminate chipped.

deb