If the front wheels are cocked at an angle, or against an object, it may be difficult to get the steering lock to release when you turn the key. Wiggle the wheel in the direction necesssary to take up the pressure pushing against the internal plate. Sometimes you have to really move the wheel, while turning the key. Don't break the key, or you will have expensive repairs before you.
But it is possible for the ignition lock to fail in the locked position, and in that case you already have that expensive repair before you.