The ornamental design for an explosion-proof lamp, as shown and described.
FIG. 1 is a front view of an explosion-proof lamp showing our new design;
FIG. 2 is a back view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a perspective view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a top plan view thereof.
The broken lines showing the structures, fasteners and grooves in FIG. 6 represent portions of the explosion-proof lamp that form no part of the claimed design.