search list with over 1 million records

Hello,

I've got a table with only 6 fields but at this time with more then 1.2 million records.
Now I'd like to search within an indexfield, shown on a list page (hide data until search is active).
The result can only be one record.

edit sql query

SELECT
*
FROM tablex

So, when the user starts searching it tooks over 15 seconds until he gets the result.

If I change the query to, lets say:

SELECT
*
FROM tablex
WHERE id>800000

(and the id of the searched record is more than 800000 of course)
it is much more faster.

But, this way is not an option because I don't know what the user is looking for of course.

Is there a way to pass the users search entry directly to the sql query?