SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6d53c304ec85f0fbdfe8f90f1e61bfe726bed75c12b1c64049752076b705d9a' 
  AND token = '86eYKxUB9u/tab35S6gscExp2V5o+qYTLQLUCU/ywPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}