SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8c7daed7ffc06798d49a443747c55de0d2de849db133bab0fec5ef489af557' 
  AND token = 'P05EPlZ5rOAp0xj2qNlIcQEiwTYvI9seGvajuLJaXgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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