ᐅ Basement storage lock (house built in 1578!) can no longer be opened

Does anyone have a tip on how to open this basement storage compartment again for me or my son? Until a few weeks ago, the key could still be turned, but now it goes into the lock without turning. Removing the lock or the hinges seems almost impossible; we have already tried oiling it, but unfortunately without success.
My son doesn’t really want to bother the very kind landlord, call a locksmith just yet, or use brute force either. Does anyone have any other ideas?

The door should be able to open over the hinges (on the right). However, this will require a replacement.
Is that wood? No, an axe will do as well.

Warranty? It can’t be right that the thing breaks down after such a short time.

Using brute force is not my first choice.

I would first spray in W40 and then try again by turning it left first and then right, possibly applying more force? If necessary, even until the key breaks. You will probably need a new lock anyway.

If that doesn’t work, then cut off the screws of the door hinges. Then the door will definitely open.

In my opinion, the landlord is not responsible for small repairs.

If the craftsmanship skills are limited, it is advisable to have a professional handle the work. However, in that case, the landlord should commission the job, as it is no longer a minor issue.

Tadaa! It’s open. But it only worked by cutting off the screws of the hinges.
And when you see the condition of the lock, it’s no surprise that nothing was moving anymore. Now there’s a new lock (new screws, etc.) and everything is fine again.
Thanks again to everyone for your help!