SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1126ff6c663471fc96095ca796972c7022fdf09de0d40b44d4bae0de8a810871' 
  AND token = '9qrVIr2PijZU9caVrlBp4jo5OKo0zKJXO/3jTnvU2FQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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