This information is found in the approach plates and Jeppesen charts. Some airports turn off the lights overnight, but if you tune a certain frequency using a VHF transmitter, and key the transmitter, the lights can be turned on/up. All aerodromes are theoretically available 24/7/365 for emergencies, but many prohibit operations between certain hours on account of noise or other facility constraints.

Exemptions can be granted in the case of IRROPs, and that might have been what you experienced at BOS.