Taking little time. Also, in its older sense, alive — the quick and the dead.
Old English cwic (alive, living), from Proto-Germanic kwikwaz, from a Proto-Indo-European root meaning to live; the sense of taking little time is a later narrowing of a word that first meant simply alive, as in the quick and the dead.
Taking little time, and in its older sense, alive rather than dead. The two meanings share one root because what moves fast was, before anything else, a sign of life still in a thing.