Its a matter of range. TKD trains for long distance kicks. Muay Thai Does intermediate and short distance. Muay Thai has the advantage by far.
What is your definition of a "real fight" might I ask?
by real fight, i mean like... REALLY fighting... like someone in a bar has decided he wants to f*** you up... or someone is trying to kill you. i never took TKD so i dont know if there are techniques intended to inflict pain and damage that dont require a whole lot of flair.