Lock Jammed for convertible trunk release lever

I have a '96 eclipse convertible. There is a lock right next to the door where the levers for the trunk release and the gas cap release are so you can lock your trunk and gas cap so no one can pull it when the top is down. I tried sticking my key in there but it will not turn. It acts like the key doesn't fit. I tried spraying some penetrating grease in the lock but no luck. I bought the car used and they only gave me one key. Does anyone out there know if there is supposed to be a separate key for this, or of not, how to fix this problem or have any recommendations?

-thanks

The key that fits the doors and ignition also fits the trunk popper lock.

K. thanks.. it must just be jammed some how. Is there a way to fix something like that?