I claim the ornamental design for a key tag, as shown and described.
FIG. 1 is a top isometric view of a first variant of a key tag;
FIG. 2 is a bottom isometric view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a left side view thereof;
FIG. 9 is a top isometric view thereof, shown in use, wherein a key is attached to the key tag using a key ring; and,
FIG. 10 is a top isometric view thereof, shown in an alternate use, wherein a key fob is attached to the key tag using elastic bands.
The broken lines shown on the key tag represent portions of the key tag that form no part of the claim. All other broken lines illustrate environment that forms no part of the claimed design.