Combine cold water, kosher salt, and honey in a large bowl; stir until salt dissolves. Place chicken breasts into the bowl and weigh them down with a plate to keep them completely submerged. Cover the entire bowl with plastic wrap and refrigerate for 1 hour.
Remove the bowl from the refrigerator. Drain and dry chicken, then transfer to another large bowl. Pour buttermilk over chicken and let stand at room temperature for 15 minutes.
Combine flour, pepper, garlic salt, onion salt, and cayenne pepper in a large bowl.
Coat each chicken breast in flour mixture until very well covered on all sides. Place flour-coated chicken breasts on a cooling rack to dry for 15 minutes.
Meanwhile, heat 1/2 inch vegetable oil in a large skillet to 350 degrees F (175 degrees C).
Working in batches, fry chicken breasts until browned and no longer pink in the center, 5 to 8 minutes per side. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).
Transfer chicken to a cooling rack and allow to cool for 5 minutes before serving.