SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35fd7f7d2ebbe7810f49759a4a6c082129b28d60eba20795a3bb0d7f9cf239b6' 
  AND token = '2LXXJoXQxTiub3xra+WcgxBFyP69ZdSm6hZM9LGUbOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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