You would need to take the inner panel off, which might not be easy as door is closed. Some forcing of the panel is required and you need to take off holding screws etc before doing that.

Hi

On the inside of the door there are two trim panels, the top section and the lower section, you will only need to remove the top section.

There are two screws, one in the inner door handle and one at the center bottom of the top trim section, remove them both.

when the two screws are removed the panel is held in by plastic clips which will pop out as you pull the trim towards you.

once its free you will see two wire arms, one is joined to the inner door handle to open your door and the other is joined to the inner door lock which your key locks and unlocks.

Pull the inner door lock wire, to unlock your door and then pull the handle wire to open your door

Leave your door open and try using graphite power inside the lock to free the seized lock or replace the lock, but you may need to change the other door locks and ignition if you don't want to use two different keys.

cheers