Screenshot with CTRL + S

here is my solution. You need to press ‘s’ within “allow” milliseconds from releasing ctrl key

boolean key1 = false, key2 = false;
int start = 0, allow = 300;
void setup() {}
void draw() {if(frameCount % 50 == 0) println(key1,key2,millis());}
void keyPressed() {
  if(keyCode == CONTROL) key1 = true;
  if(key == 's') key2 = true;
  if(key2 && millis() > start && millis() < start + allow) { println("take screenshot!"); }
}
void keyReleased() {
  if(keyCode == CONTROL) {key1 = false; start = millis();}
  if(key == 's') key2 = false;
}

I find allow 300 to be the best. You can obviously configure it to your liking