SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '318caa2d6353067a31c636c261fd9c54bc57e67458080797f8ae51d13b14138b' 
  AND token = 'KKhKn6t0Ui9C6V79SeN89NHKOibWO1Epg/+T5uLZWMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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