SELECT first 1 ITEM_DATE FROM HISTORY

WHERE ITEM_ID = 'ITEM_ID_123456'

and ITEM_TYPE = 'TYPE1'

AND ITEM_STATUS > 200 and ITEM_STATUS <> 310

ORDER BY ITEM_DATE ASC

Which runs in about 1.5 seconds. If I remove the Order by it's less than 100ms. There are only three records in the result set. There is an ascending index on ITEM_DATE and the statistics are up to date. 

Does anyone know why there would be such a difference in performance when using\not using the order by? What is the engine ordering? It can't be the three records to take 1.5 seconds, surely?

Thanks,