I don't think the key should be classified as an artifact because it is more of a secret without that name. I already found that gate, it does nothing but is slightly open. It is probably a good thing that you can't go through it, though, as we are 3 stories high. I found it in a more recent livestream I did of the new update. I made it nearly a week ago.
Viewing post in Advanced Education with Viktor Strobovski comments
Not really more of a "secret" , finding the room with the key and figuring out what to do with it later should be the secret. I actually tried to place the key in my belt on an earlier version, nothing happened. In a newer version, you can...all-of-a-sudden...
Had a feeling you already found this, just thought I post something.