SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e85f663de4e1439f9c3552914b13078db9d24948011e1e92231127f03ca049d7' 
  AND token = 'OzHdLK5Pjk7NYHAE7/UghrAjS8GoXybB6hItl3On4Wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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