My cousin could not unlock the garage to retrieve her mum's wheel chair to take her to hospital.
Screwdriver and pliers in hand I go to the rescue. I too could not turn the key the whole way to release the lock. It moved quite freely at first and then just stopped. No mechanical noise to indicate something catching.
Then I noticed yellow pollen trickling out of the key hole. So by jiggling key I gradually removed a batch of pollen so that the key could be turned sufficiently to release lock.
Once door was open I removed lock and took apart to reveal small grub and rest of pollen packed behind lock bar. This polenl was acting like a cushion and stopped the bar from moving over. Easily fixed bit bad news for the grub.