I know that similar questions have been asked here, but I can't find a question with the exact same problem encountered here.
My bike was left locked during a week or two of sub-zero temperature, and another week when my wheel was punctured (almost three weeks I think). And the day I started riding it again, I felt the lock started to jam but managed to lock the bike anyway.
Now since a week ago I cannot unlock it: The key goes in but doesn't turn at all (I bought the lock less than a year ago). I've suspected that water froze inside the lock, and so I've applied some water displacer in it (gt85) which has worked last time it has jammed, but not this time.
Is there any hope to unlock it if I use a lubrificant? And what type of lubrificant should be used?