The exposure and composition are good. I like this also. It looks like a normal distrubition of light and dark. Low key is more than just a dark picture. It is more about painting with shadows. I just don't get that feeling with this picture.
I find this definitely falls into the "low key" category, yet is distinguishable as to what it is. To fit the title more, I would've closed in to about 35 percent of the "sandals" and the fence in the "background".