I think the picture could do with a slight increase in 'levels' and brightness, but not too much. There is a very fine balance between having a technically-perfect, well-illuminated picture, and destroying the effect or ambience of the scene.
So a "low key" shot is really OK, just be sure that is what you are trying to achieve and communicate. Perhaps do two or three versions and pick the one that is the most appropriate for your work. Nice card too.