Either is grammatically acceptable.
However, individual pairs of shoe laces usually don't come in a box. Typically they are just wrapped with a band of paper or plastic, or maybe taped/tied to a piece of cardboard. Sometimes they aren't even enclosed in plastic. I'd use the term 'pack' or 'package' instead of 'box'.
I suppose stores that sell shoelaces might receive boxes of multiple shoelace pairs, for merchandise stocking, but as far as I've ever seen, individual pairs of laces don't come in boxes.