SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9208e7c768230292e654eacd2c25a2ab49054b73707ed5a564445ee12ca43ccb' 
  AND token = 'O9pbJw+qyqMpQtPwhusso0Htqz9GutUhANiHFa5BUMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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