ST_Crosses(g1, g2)

Two geometries spatially cross if their spatial relation has the
following properties:

o Unless g1 and g2 are both of dimension 1: g1 crosses g2 if the
  interior of g2 has points in common with the interior of g1, but g2
  does not cover the entire interior of g1.

o If both g1 and g2 are of dimension 1: If the lines cross each other
  in a finite number of points (that is, no common line segments, only
  single points in common).

This function returns 1 or 0 to indicate whether g1 spatially crosses
g2.

ST_Crosses() handles its arguments as described in the introduction to
this section except that the return value is NULL for these additional
conditions:

o g1 is of dimension 2 (Polygon or MultiPolygon).

o g2 is of dimension 1 (Point or MultiPoint).

URL: https://dev.mysql.com/doc/refman/8.0/en/spatial-relation-functions-object-shapes.html

