If you match candies under the dispensers at the specific move (see my previous comment), the key DOES drop. I have replayed this level several times and all keys drop at the move they suppose to drop. Don't bother to destroy the block much. You can destroy only one of it to get a colour bomb (or just make a colour bomb by…
I've been on level 599 for weeks and decided it just wasn't fun any longer. I deleted the game and I'll find something else. It was a fun app overall, though. I'm glad it's gone. This level wasn't worth the effort.