SELECT forum.*
,
IF(forum_read.forum_read_date > 1416086650, forum_read.forum_read_date, 1416086650) AS forum_read_date
FROM xf_forum AS forum
INNER JOIN xf_node AS node ON (node.node_id = forum.node_id)
LEFT JOIN xf_forum_read AS forum_read ON
(forum_read.node_id = forum.node_id
AND forum_read.user_id = 275)
WHERE forum.node_id IN (2400, 2405, 12, 1745, 148, 43, 42, 117, 181, 1277, 1279, 174, 30, 2897, 1286, 2180, 32, 118, 2534, 2290, 2038, 1696, 1985, 1933, 45, 120, 2406, 4, 206, 1930, 5, 215, 226, 2776, 224, 2779, 2778, 2666, 501, 23, 6, 2759, 2760, 249, 2753, 2754, 1517, 1518, 159, 704, 2206, 2207, 2260, 2261, 2718, 2719, 1848, 1849, 2683, 2684, 373, 705, 2328, 2329, 2208, 2209, 2493, 2494, 2491, 2492, 2889, 2890, 2107, 2110, 2108, 2111, 2587, 2588, 2109, 2112, 156, 708, 2254, 2255, 2256, 2257, 2258, 2259, 2736, 2737, 1945, 1946, 2193, 2194, 2537, 2538, 2879, 2880, 2551, 2552, 2560, 2563, 2561, 2564, 2562, 2565, 1941, 1942, 2380, 2381, 2382, 2383, 2384, 2385, 2509, 2510, 836, 837, 2364, 2365, 1556, 1557, 1863, 1864, 164, 710, 258, 713, 2845, 2846, 1147, 1148, 656, 717, 163, 326, 327, 328, 198, 2531, 2532, 2661, 2662, 2397, 2398, 2831, 2834, 2458, 2459, 2637, 2639, 2638, 2640, 2832, 2833, 1713, 1714, 2891, 2892, 301, 302, 303, 304, 440, 655, 718, 2412, 2413, 2245, 2246, 1882, 1883, 375, 489, 490, 491, 463, 1949, 1950, 111, 168, 443, 444, 445, 123, 196, 201, 233, 238, 261, 697, 720, 1574, 1575, 698, 719, 2009, 124,
...multiply this by about 15, had to remove for character count in postings. But is is 2500 node ids.)