Trunk won't open

Has anyone experienced issues opening their trunk with key? Key fob works fine but trying to open with a key won't work, key goes in but won't turn. Any info regarding TSB's Recalls or how you resolved the issue would be appreciated.
 
Just curious - how old is your ride? If older, and bad weather plays a role, using some graphite in the lock might help? Just don't use WD40, and don't ask me how I know that! Let us know?
 
Tri-Flow

I had always used WD40. Recently locksmith said only lube to use is Tri-Flow. I live in a desert area and this lube doesn't attract sand and dust. Put it in some sticking locks and it works great.
Added: Most likely find it in a bike shop.