Search is slow in a partitioned table
You seem to have an issue with key distribution with id and the Query Optimizer.
Since the id is not being factored into the partitioning scheme, I only see MySQL having to look up the id up to 6 times. Depending on when and how frequent each id value is written, the query could be using the wrong index.
There are two things you could do to see if id key distribution is at issue
SUGGESTION #1 : Run EXPLAIN on each query
explain select *
from table
where id='25885'
and clock&gt;1476044179
order by clock desc
limit 3;
explain select *
from table
where id='24946'
and clock&gt;1476044179
order by clock desc
limit 3;

The output will tell you what index was chosen to scan for rows. If the clock index is being used, then the clock is being scanned in the index, but the id is being scanned from the table.
SUGGESTION #2 : Change the ORDER BY
If the order by clock desc is making the Query Optimizer choose the clock index, try this:
order by id,clock desc

That way, the scan will be from table_1 index, starting from the last time anid was inserted.
GIVE IT A TRY !!!