SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b60edba26e93749f4ea1b08ccefa18cb393fbc511be224a7ff5627b00fe7ee' 
  AND token = 'WIqsH+gq7FD+YpvP8Nd5Mr4LuLFrAAAkxBgerz2Xa0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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