SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cddff301d43bcfb377dad834a9da0cc297cede75778e0ad52702bd1f8fff7e5e' 
  AND token = 'qnusyAabBiw79zfpbR+Wyc4zmrEeSWejmtwBTtvSWzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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