This might sound kind of brutal, but might be worth a try. First disconnect the negative battery cable. With a spare key (one you can throw out when done), with only the key in the ignition and all other keys and ring off the ignition key. Try tapping moderately at the key ring end of the key (towards ignition lock) with a small hammer. At the same time, try turning the key. Keep trying for about 5 minutes. Chances are if you tow it to a dealer or shop, they will try the same procedure before hammering or drilling out your ignition lock cylinder. Also make sure you have an extra key, or even have one made for this task, as you might damage the transmitter part of the key you’re hitting on. I’ve seen this problem I don’t know how many times, and next to making sure the key is good and not worn out, it’s the first step I will try. If your think you’re mechanically inclined enough to replace the lock cylinder after you free it up, you will need to have the ignition in the run position to remove the cylinder (so will the dealer or repair shop). Some or most of the times I’ve had to do this, the key would turn without further concerns. | 
