SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a84cee394b21235bce59e8cdcbb7349fbae0ab4eb606440008d3598b262bd739' 
  AND token = 'HQCdLEMMQJmC98NwvVPn7Wamllb5b31fQpupDz8MitU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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