Can someone using a discern location spell find someone using mind blank spell?
No. While the discern location spell description contains some pretty strong language about the spell’s ability to overcome effects that block scrying of divinations, the general rule in the D&D game favors defense over offense, so mind blank’s ability to block scrying and all forms of divination trumps discern location’s ability to penetrate such defenses.
Blocking spells of 7th level or less, however, are still ineffective against discern location.