Make video look like it was shot in a dark room
You are lucky that you don't have extreme lighting conditions in your shot, also you're indoors. So it should definitely be possible to get the footage a bit darker looking without making it look weird.
I can recommend working in After Effects rather than Premiere, its far more suited for advanced lighting correction.

I would start by masking the already dark areas of your footage and make them even darker. Try to create a more focused looking light that's coming from the light bulb/screen or whatever light source you want to have. If you want to create new light sources you will also have to make some masks to emulate the way the light would shine on the surrounding objects.
The whole part behind the chair should be a lot darker.
Generally make everything that is already in a shadowy area even darker and lower the brightness of the image overall to a point that feels good.

Also something that should help is this (bit dated) tutorial by Andrem Kramer. Its not perfect but definitely a good help to figure out the workflow:
http://www.videocopilot.net/tutorial/day_to_night_conversion/