Take them both to a locksmith and have him re-pin the core to fit your key. Alternatively, he could cut a new key for you that fits the lock. Either way.
This. The guy that lived across from me worked doing locks and auto entrance doors. He had a desk in his van with tools and key machine.
We lost the keys to my tool chest. He picked the lock quickly. Then removed it. Re keyed and made new keys l. He also rekey some locks from numbers no locks or keys. Locks keep honest people out. Scary fast when someone knows how to pick a lock