The ornamental design for a smart cardreader, as shown and described.
FIG. 1 is a perspective view of a smart card reader, showing my new design;
FIG. 2 is a perspective view of close state 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 plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The dashed or broken lines shown in the drawings depict portions of the smart card reader in which the design is embodied that form no part of the claimed design.