often there is a number on the lock. write down the brand and the number and go to a locksmith and they likely can make you a key.
and the ubiquitous CH751 key. what does it work on
1) almost all keyed baggage compartments
2) almost all riding lawn mowers
3) most lock boxes for sprinkler systems etc.
4) a large number of smaller tractors, backhoes, etc.
and the list likely goes on and on.
First thing I did on our trailers is take the baggage locks to a locksmith and have them rekeyed so the CH751 won't work. Still keep a CH751 on the keyring, have occasionally helped another camper who lost a key.