The invention relates to a water borne coating composition comprising a) a polyol, b) a polyisocyanate crosslinker, and c) a thiol functional compound, wherein the molar ratio of isocyanate groups to thiol groups ranges between 1:0.0001 and 1:0.4. The invention further relates to the use of the coating composition, and to a kit of parts for preparation of the coating composition. The coating composition according to the invention displays a balance of high curing rate, long pot life, and good film appearance of the coating prepared from it.