Stitchnripper,
Do you have any idea what shape the key is supposed to be?
Is the key hole a straight line up and down, side to side, diagonal,
Triangle shaped keyhole,
Or skeleton key hole: round end but long straight body?
If it is only one straight line/slot, look around for a very very tiny screw driver like for tightening eyeglasses. Gently, gently see if it will loosely fit through the slot enough to engage the inner lock parts. Maybe 1/4" or a touch more.
Now, on a drawer that is not locked, take the drawer out of the cabinet so you can watch the lock and won't accidentally lock a second drawer ;-)
Try the small screw driver in the drawer lock you are holding, softly, softly twist the screw driver between two finger tips.
Do not grip the screw driver in your palm with a full hand and give it a big turn. If you use too much force and the lock is weak, you will probably break the lock or your drawer.
If you are lucky enough to have the right small screw driver, and the lock won't turn, oil it, leave it sit for a while, go back and gently jiggle and try again. After a couple of oilings it should turn.
If you get the hand of turning the lock on the drawer that you are holding, then go to the locked drawer in the cabinet and give it a go.
If you have a lock that is triangular, or skeleton, I haven't found a safe tool yet to get those open, but there are many keys on eBay for $4.00 to $9.00 each day.
Let us know how it works out.
Aardie.