SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fc038d660d20098cbfac80d0ee2f5d832314b50f83a0af004716461dc619eb7' 
  AND token = 'jTzfciqH24All1Myjij52ZEVjvrqTwf2zIoWkZJv0yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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