You can access the Chart Controls/Navigation menu by clicking the icon in the lower left corner. You have the option to Reset the x-axis, y-axis or both from this menu. It will also provide the appropritate shortcut using the Enter key.
The ellipses icon below the Y-Axis also provides a Reset to Default.
You can also use the ENTER key as a shortcut. Hit Enter once to reset the Price Y-Axis. HIt it a second time to jump to the current bar. Hit Enter a 3rd time to rescale the Time X-Axis.