The ornamental design for a smartlock with a graphical user interface, as shown and described.
FIG. 1 is a front perspective view of a smart lock with a graphical user interface according to my design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a front elevation view showing the display of the smart lock with graphical user interface in use in broken lines.
The evenly spaced broken lines shown in the drawings are for the purpose of illustrating environmental features that form no part of the claimed design.