EK384 leaves BKK for HKG but not at the time you say. If your leaving at 01:35 I expect your travelling on EK385 to Dubai.

If I'm right the flight before yours is at 21:20 and check in closes between these two despite the posts above, unless it's changed in the past few months.

BKK often has one desk open throughout but it's not guaranteed - I've been there to check in for EK385 with nothing open because I'm too early.