The poem looks back at the past in three short glimpses, and each one feels different. First the past is distant and chilly, compared to "a god of business": something powerful and impersonal that doesn't care about us. Then the speaker gets closer. They "eat" from this past, taking it in like food, but it's almost too much, a little sickly sweet, as the word "cloyed" suggests. Finally the past becomes a shared "feast," something the speaker and others have gathered around, yet "the lock altered" hints that something has changed. Perhaps the way back in is no longer the same, or the past can't be reached as it once was.
The speaker seems wary and a bit uneasy rather than simply nostalgic. They need the past and feed on it, but they also feel its coldness and its excess. The mood is quiet, compressed and slightly unsettling, with a sense of loss tucked inside the images.