In stark comparison (ha ha, stark) to someone else's difficult time getting into the club, Loki had entered through the front entrance using a blank card that other people would see as a New York drivers license of a male in their thirties. He breezed his way over to the bar, seeing Tony Stark looking antsy. That was too rich (also ha ha) because Loki simply layered another spell over his usual disguise, so Tony wouldn't see him.
That way he didn't have to ruin the fun of the talkative billionaire looking like a Midgardian youth.
Loki made his way over to the bar and ordered a drink, a mischievous smirk on his lips.