Try using DATEPART. You can then perform filtering based on specific parts of the date and time (month, day, hour, minute). It would look something like this (untested):
RsHistory.open "SELECT *,(SELECT COUNT(*) FROM ecard_history WHERE ecard_history.date_created>=DATEPART(hour,GETDATE( ))-1 AS Rec_COUNT from ecard_history",Conn,3,3
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