When I lock my 1999 ford power locks i can't open with a key?

When I lock my 1999 ford power locks i can't open with a key?

Cars that have remotes to unlock the doors means that the key never gets used and the locks get corroded inside. Try the key in the trunk or the other door to make sure its the right key. Get some penetrating oil with the red tube on the can and stick it in the lock and spray it inside all the locks