Subjunctive with ἄν, when the action lies in the
a. Future, and the main clause contains a verb referring to the future (except the optative without ἄν). The tense is usually the aorist: the present marks overlapping.
b. Present, and the verb of the main clause states a present customary or repeated action or a general truth.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].