I think the marriage record is about 40 minutes by Stardew speedrunner Haboo, marrying Shane. He's the fastest because he's out of his front door just after 7am, rain or shine, so you can chat and gift him very early in the day and get back to sleep. The other NPCs loiter behind locked doors until much later in the day. You can also just buy him loved gifts (Beer) for cash at the saloon.
Myself I've done it in about 55 minutes, using a similar route in rather less expert fashion