Fun fact: any chest that is unavailable right now is just a decoration. It doesn't have any item, nor even collisions. In the new desert area it's even more - nothing that can't be reached normally has any collisions, so all chests and season orb and even walls, they are all immaterial decoration. What's more unique, you can't even change screens, becaue borders do nothing too.
Not sure if you can reach that room, but I suppose this chest is disappointingly immaterial too, so it doesn't have any content.