NoSQL approach: design table "scheme"
w/o any secondary index I can think of PIVOT. (Data in Key-Value pair way)



Depending on the usage and query you are expecting you need to decided if key "LogText" needs to go in to another table or ok to put in Table-2. 

You can have key on both columns and that will give you option of defining local secondary index to improve performance for complex queries like

ALL DATA where (TimeStamps is between x and y) and User = "ABC"

this can be done in two steps, 

select ALL data where KeyIDs are IN 
( get unique KeyIDs for that satisfy this WHERE conditions.)