KE is a new member to TSA PreCheck but it has been a few weeks so the system should be operating. PreCheck at JFK Terminal 1 seems to be PreCheck Lite where you go through the same line/wait but get to keep your shoes & belt on for the metal detector unless "randomly selected" for the scanner.
TSA pre check at JFK T1 Has some comments. The info about KE not participating is out of date since the end of October. This may vary depending on which flight to ICN you'll be on.