Basement key use

[TimeLord]

Does anyone know how or where to use the basement key, or is it not possible in the demo ?

[Salt Shaker]

Also curious about this, guessing it's the location of one of the gas valves?
Might also be related to the spot of barren soil from the map in the orchard, but that area is so close to the start that its almost never locked, so that could be a red herring.