SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '09da97748ff5f8b924a9536917d0972b3a00210d03e7a081a7e0c58a79c6e5b1' 
  AND token = 'yoJKuzwqvlw5mzyQ9EepQrBt4L0mFSXYiCyHXCqYgSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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