The answer- in English- is plural, present tense (as in "The good ones beat...") which is the direct translation of "הטובים מנצחים את הרעים ". The confusion arises in English because the plural past tense uses the same form of the verb as plural present tense. In English it isn't possible to tell from this sentence whether one is speaking about something ongoing in the present, or about a past event. The Hebrew word endings avoid that ambiguity.
P.S. If it were singular present tense, it would be "beats" (see comment by amyleebell above).