Time is the main thing. It will ferment at any above freezing and below boiling temperature.
The use of a heating pad is really determined by your environment and the yeast and your flavor goal. What was it... warmer for fruitier/esthers (ales, reds), and cooler for crisper(lagers, whites)? Montrachet's temperature range is 59-86 (a wide range depending on style, and even if it was below or over, there's still working yeast at those temperatures, just not as many and there's no recommendation on going outside of the range anyways. Bad stuff flavorwise.)
With your ambient temperature of 64, I would not use a heating pad. That's a great temperature to be at. If you're doing this in an outside, mostly unheated shed, then I would use a heating pad. (Actually, I have a furnace and a water heater in my outside room, so it's never below 50. It still counts.)
Secondary: GF Czech Lager
Waiting to be kegged, Italian Primitivo
Kegged&Ready: GF Orange&Coriander, GF Honey Lager, GF chocolate ale, GF English ale, Island mist (zinfandel), Island mist (cbry malbec).
Bottled: Infected Mead, Dry Hard ciders, Accidental Sorghumwine, various unnamed.