Replacement key for an old sewing machine?
To pick a lock like this, you may be able to simply push a paperclip into the keyhole.  If you normally put the key in pointed down, try to find a lever to press up or to the side within the top or side part of the lock.

If you're not able to pick it, then it depends on the design of lock as to whether you'll be able to slide something into a crack to push a spring loaded latch to the side.  You may also be able to drill a hole from beneath the machine to access the lock or strike plate where it won't be visible.

Once you have it open, either remove the lock, remove the strike plate, or fix the strike plate so that the lock is not able to catch.