Help: Long Lasting Crisp to KFC

I think that Korean Fried Chicken (KFC) is the best kind of chicken (so long Southern style Chicken). I have been trying to make the fried chicken but to no avail can I get the same long-lasting crispiness that is present in the KFC restaurants and stores. I really want to make my own super crispy and yummy chicken like Boom Boom or Bonchon Chicken. Even after several hours, their chickens are still crispy. But those chicken shops are so expensive! PLEASE HELP ME TO ACHIEVE THE PERFECT KFC!!!! <3

Sincerely,
Jenny