SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '305ddba6799e26b7b783dafe4f6dd04207f5250fba71592e63d9b1b49a911639' 
  AND token = 'ytFJf2LseZ9OejnxK1lPnvlJO5ikYr9pQZ1z0bHBh3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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