Under Settings » Data inputs » Salesforce Event Log » EventLog
Get event log data from Salesforce.com.
Query Start Date:The initial date/time to use for the first query. If nothing is specified, the query will default to starting 90 days prior the date of the first run.
I tried the following to ignore Eventlog events earlier than 2/1/16, however it still receive events prior to that date.
1454284800000 (epoch time for Mon, 01 Feb 2016 00:00:00 GMT)
This appears to be the correct format. 2016-02-01T00:00:00.000Z
The issue was that the constraint is only honored for a new input setup . Changes are ignored if you edit after the setup. Workaround was to clone the input, add the constraint and to disable the old input.