I highly doubt it's rusted into place. They key needs to unlock it, then the green part pulls out then you twist. Many people miss the "green part pull" part and then just try to twist it.
I lost the key for mine. Had to punch the roll pin for the handle out, remove the handle and shave of the plastic tab so the key isn't needed. It has a been a few years so maybe some one can fill in some blanks.The plastic handle pulls out then rotates about a 1/2 inch then stops. Is the key always needed or can you have it locked or unlocked ? No key for it.
Dealer 300 miles away told me local lock smiths can make a key useing the # on the key hole if they have the right blank. Local guy had no luck with the number and tryed to pick it, but its froze up. I'm thinking sledge.If you lose the key you can have the lock mechanism removed and replaced by the dealer. When bought my LR3 several years ago it had the hitch receiver attached but there was no key. Dealer charged $100 for a new lock.
Any wags, even if it is rusted in place, a few raps on the side with a sledge will free it up.