Creating indexes on AutoId and time column
For history tables such as this one, it's often appropriate to create the clustered index with a date field as the leading column, and have the primary key index nonclustered.

In this case, since you know EventTime is non-unique, you can add the AutoId column to the key to make it unique (instead of relying on a uniquifier).

This is how the clustered index would be created (after first dropping the existing primary key constraint):

CREATE UNIQUE CLUSTERED INDEX IX_Events_EventTime_AutoId
    ON [Events](EventTime, AutoId);


And then recreate the primary key:

ALTER TABLE [Events] WITH CHECK
    ADD CONSTRAINT PK_Events
        PRIMARY KEY NONCLUSTERED(AutoId);


This setup allows for efficient date-range-based queries like the examples you've provided, and still doesn't create too much fragmentation to the base table as the clustering key is generally ever-increasing.