Krsna is not sleeping at all ... He's making fun.
"Mother Yasoda put Krsna to sleep and went to her bedroom, leaving servants there to watch Him. Krsna closed His eyes for a few moments and a short time after that He got up and secretly closed the door outside of which the servants stood and went out of the side-door. He quickly went out, eager to meet Sri Radha in the Nikunja.
While walking along, Krsna thought: "The city gate is uncovered and bathing in moonilight. People are constantly going there. Let Me blissfully take the road behind the house which is shaded by trees!"
While Krishna walked, the ground of Vraja kept Him on the engine of her lotusheart, so that He swiftly moved with the speed of the wind towards the Nikunja-cottage with His Radhika. It seemed that Krsna arrieved there just by thinking of it.
Krsna quickly proceeded, anxiously thinking to Himself: "I left the moonlit path, taking the road which is shaded by trees. Has Priyaji come there yet or not?" (Govinda Lilamrta - 21, 102-106)
