Declare @string varchar(50) = 'abcd [[% SQL Server %]]' -- Matched

/* LIKE []:          No Matched */
select case when @string like '%[[][[][%] SQL Server [%][]][]]%'
          then'Matched' else 'No Matched' end

/* LIKE ESCAPE:      Matched */
select case when @string like '%?[?[?% SQL Server ?%?]?]%' ESCAPE '?'
          then'Matched' else 'No Matched' end
          

/* LEN & REPLACE:    Matched    */
select case when len(replace(@string,'[[% SQL Server %]]',''))<len(@string)
          then'Matched' else 'No Matched' end

Declare @string varchar(50) = 'abcd [[% SQL Server %]]' -- Matched

/* LIKE []:          No Matched */
select case when @string like '%[[][[][%] SQL Server [%]]]%'
          then'Matched' else 'No Matched' end

declare @search_pattern_should_be varchar(100)
set @search_pattern_should_be =  '%[[][[][%] SQL Server [%]]]%'

--example
select case when @string like '%[[][[][%] SQL Server [%]]]%'
          then'Matched' else 'No Matched' end