SELECT a.*
    FROM turtle_derby AS a
    INNER JOIN (SELECT turtle_id, DATE(`date`) AS day_date, MAX(`date`) AS maxdate
    FROM turtle_derby
    GROUP BY turtle_id, day_date) AS groupedtt
    ON a.turtle_id = groupedtt.turtle_id
    AND a.turtle_id = '175846'
    AND a.`date` = groupedtt.maxdate
    AND a.`date` > '2018-07-26'
    ORDER BY `a`.`date`