Unfortunately Bossiaea prostrata and Bossiaea buxifolia are extremely difficult to tell apart from a photo. In buxifolia there is no join in the leaf stalks, and the back of the standard (upright) petal is darker. In prostrata there is a join in the leaf stalks and the back of the standard is lighter pinkish brown.
Although a definitive identification can't be made from the photo. I think the small size of the leaves, their close spacing and what appears to be a short flower stem suggests that this is most likely Bossiaea buxifolia