how to optimize mysql query to get faster result

Question

i have 3 table

1)files: files main data

2)user_files : user info

3)file_pages : each page of the file have a row in this table and have a field as page_content with FULLTEXTindex

for search i wrote this query

SELECT * FROM files 
    right join file_pages on files.id = file_pages.doc_id 
    right join user_files on files.id = user_files.file_id 
    WHERE (files.status='C' or files.status='L') and (
    (user_files.description LIKE '%space%')
    or
    (user_files.title LIKE '%space%')
    or
    (file_pages.page_content LIKE '%space%' )  group by files.id

this query result : Showing rows 0 - 24 (399 total, Query took 6.9195 seconds.)

but when i search without join

SELECT * FROM `file_pages` WHERE `page_content` LIKE '%space%' 

the result is : Showing rows 0 - 24 (7973 total, Query took 0.0026 seconds.)

with join my query take 7 second but the main part of query just need 0.002 second to execute

now my file_pages table is small and have about 10k row , but when it grow and got 100k row my search time increased to 120 seconds

how can i get a better speed?

Update: it seems this is not related to using “like” and wildcards because when i remove a part of my joins

SELECT * FROM files 
    right join file_pages on files.id = file_pages.doc_id 
    WHERE (files.status='C' or files.status='L') and 
    ( file_pages.page_content LIKE '%space%' )  group by files.id

this took Showing rows 0 - 24 (399 total, Query took 0.7110 seconds.) compare with first query!