Let G be a graph and k a positive integer. A strong k-edge-coloring of G is a mapping φ : E(G) → {1, 2, . . . , k} such that for any two edges e and e that are either adjacent to each other or adjacent to a common edge, φ(e) = φ(e ). The strong chromatic index of G, denoted as χ s (G), is the minimum integer k such that G has a strong k-edge-coloring. Lv, Li and Zhang [Graphs and Combinatorics 38 (3) ( 2022) 63] proved that if G is a claw-free subcubic graph other than the triangular prism then χ s (G) ≤ 8. In addition, they asked if the upper bound 8 can be improved to 7. In this paper, we answer this question in the affirmative. Our proof implies a linear-time algorithm for finding strong 7-edge-colorings of such graphs. We also construct infinitely many claw-free subcubic graphs with their strong chromatic indices attaining the bound 7.