[Cank]

Код:

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
   if(IsPlayerInCheckpoint && newkeys & KEY_FIRE) //use the key you want instead of "KEY_FIRE", see here: https://sampwiki.blast.hk/wiki/GetPlayerKeys
   {
      //your code
    }
}

you can only use SA specific keys (e. g. KEY_FIRE or KEY_ACTION) and not something like "F" or "A" so you have to choose one from the given link.