SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409660771cc26a7c2642380d8239acfcfd119d6222a4020518060c046916b74c' 
  AND token = 'Q4JiO8Feph4wFctI+9ZGQSvRewR1NfbVajQfYaDycms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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