This is a breakup song told by someone who knows it is over and has made peace with leaving. Gera MX opens with the hook: "Sé que tengo las horas contadas" (I know my hours are numbered) and "Sí o sí íbamos a terminar" (one way or another, we were going to end). "Sí o sí" is a really handy phrase: literally "yes or yes", it means it was going to happen no matter what.
The heart of the song is one image: "Porque tu amor es como una jaula / Y a mí solo se me da volar" (Because your love is like a cage, and all I know how to do is fly). Later he sharpens it with "La jaula, aunque sea de oro, sigue siendo jaula" (A cage, even a golden one, is still a cage). The title fits the same idea: "El reloj del corazón parece que ya no funciona" (The heart's clock seems to have stopped working).
The rap verses are packed with rhymes, and some lines are pure drama, like "El primer beso fue gloria, el último fue muerte" (The first kiss was glory, the last one was death). One fun idiom for learners: "mi camino no va a Roma" (my road doesn't lead to Rome) twists the saying "todos los caminos llevan a Roma" (all roads lead to Rome), so he is saying his path no longer leads anywhere. He is not bitter, though. He asks her to "Cumple todos los sueños y metas que tenías conmigo" (fulfil all the dreams and goals you had with me) and just let him go: "Solo déjame volar" (Just let me fly).