The ornamental design for a solar-powered toy car, as shown and described.
FIG. 1 is a perspective view of a solar-powered toy car showing my new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The dot-dot-dash broken lines are included for the purpose of illustrating the bounds of the claim, and all other broken lines shown are included for the purpose of illustrating portions of the article that form no part of the claimed design.