MBROverlaps(g1,g2)

Returns 1 or 0 to indicate whether the minimum bounding rectangles of
the two geometries g1 and g2 overlap. The term spatially overlaps is
used if two geometries intersect and their intersection results in a
geometry of the same dimension but not equal to either of the given
geometries.

URL: http://dev.mysql.com/doc/refman/5.6/en/spatial-relation-functions-mysql-specific.html

