I've never picked one of those fuel door type locks before, but I have done others.
If you have an other tank with the same mechanism you can study it and figure out what needs to move to pop the lock open.
If you've changed the wipers on your car lately, save a blade. Often there is a thin, but strong metal strip inside wiper blades. From there, you can bend it in such a way to catch and pull what you need to pop the lock. If you don't care about the lock, you can always just jam a screw driver in there and twist real hard. These old locks are not as sophisticated as car locks.
From there, I've disassembled locks and pulled out all the pins that make is specific to a key. Reassemble then any key will turn it.
If you don't want to go through all that, often there will be numbers stamped one the face of the lock. Either a Honda dealer or some places on the internet can make a key from those numbers.