Product review (1 stars): Some Things Shouldn't be Made Out Of Plastic
Don't bother.  The plastic key strips very easily in a metal lock.  Literally the equivalent of those plastic cut credit card keys to actuate a deadbolt.  Will work for a few times but that's it.  If you are concerned about your kids getting stuck inside, get a child proof latch like what you might find for a cabinet.  Because this key strips so easily, you are more likely to be unable to open the freezer in case of an emergency.