select sectionnumber from land.fisgridsection_vw
where sde.st_overlaps(sde.st_buffer(
(SELECT shape FROM land.fisgridsection_vw
WHERE sde.st_intersects(sde.st_point(792026,335093,2274),shape) = 1),1),shape)= 1;
Honestly, it is really difficult to troubleshoot performance issues like this in the forums unless you can provide a whole lot more information about the data, SQL execution plans, etc....
Since this involves multiple spatial operations, have you broken the problem down to see at which step the execution time increases the most? For example, how long does it take for:
SELECT shape FROM land.fisgridsection_vw
WHERE sde.st_intersects(sde.st_point(792026,335093,2274),shape)
a