I dont know if there is one ...but I use W and E to go to either In or Out Point.
I dont see the need to be close in on the clip .. as long as I am at the particular point I am trimming. ie.I can see the frames on the monitor and I rarely drag the I / O Markers around in the bar.
FWIW - at the point ...I hover over the monitor screen and use the scroll wheel to finely navigate the frames...then set a new I or O.