SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '480c03664b8434c8fb076200f479c21c218ef23d90cf53a5f85efa346849abb0' 
  AND token = '30k/jpf0/79YJhT+sRNxIUUDIF5XQbw7wzY5nDVNtjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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