The ornamental design for a sharpenerkeychain, as shown and described.
FIG. 1 is a top, right-side perspective view of a sharpener keychain in an open configuration, showing the new design;
FIG. 2 is a rear elevational view thereof in a closed configuration;
FIG. 3 is a front elevational view thereof in the closed configuration;
FIG. 4 is a left-side elevational view thereof in the closed configuration;
FIG. 5 is a bottom plan view thereof in the closed configuration;
FIG. 6 is a top, right-side perspective view thereof in the open configuration; and,
FIG. 7 is a top plan view thereof in the closed configuration.
The broken lines in FIG. 1 depict environment and form no part of the claimed design. The broken lines in FIGS. 2-5 depict parts of the sharpener keychain that form no part of the claimed design.