计算结果宽度全文搜索mysql中的行数

I would like to ask if anybody can help me with this query

SELECT count(MATCH(product_text) AGAINST('lorem*' in boolean mode)) AS score FROM table_products WHERE MATCH (text) AGAINST ('lorem*' in boolean mode) limit 0,50000

There is fulltext index on column text. A.m. query return sum of rows as score. What I wont is to count fulltext search results. If the number of results(rows) is higher than 50000, than count-sum 50000 will be returned, otherwise the exact count of of results is returned.

Problem is that it is not fast on table width 1,5 million rows if user try to find for example word "lorem" and this word appears in table f.e. more than 500 000 x.

I tried also

SELECT id,name,product_text,price, MATCH(product_text) AGAINST('lorem*' in boolean mode) AS score FROM table_products WHERE MATCH(product_text) AGAINST('lorem*' in boolean mode) and show_product='1' limit 0,50000

... width php mysql_num_rows

Another problem is that in following query mysql use fulltext index only and sort by another column or by score is than slow

SELECT id,name,product_text,price, MATCH(product_text) AGAINST('lorem*' in boolean mode) AS score FROM table_products WHERE MATCH(product_text) AGAINST('lorem*' in boolean mode) and show_product='1' order by score desc limit 0,50000

resp. (..order by name, order by price)

Is there another better and faster way?

Many thanks for any help.