Auto parts stores will have a stick of a wax-like lubricant specifically for sticking locks. Rub it on both sides of the key, insert the key and remove the key a couple of times to help distribute the lube. Then put a little more on the key, insert it in the lock, and _gently_ turn the key. If the key turns just a little, then sticks again, back out, and try it again. It might take several attempts to get the lube worked into all the areas of the lock that need it.
If you turned the key hard enough to bend it, you may have damaged the lock internally, so this might not work. If that's the case, you'll probably have to get the lock replaced.