Need help with slow query

Hi,

I have this query running it runs allot and take a long time

SELECT   wp_posts.* FROM wp_posts  INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) WHERE 1=1  AND ( wp_term_relationships.term_taxonomy_id IN (2,43,6,7,8,9,10,11,12,13,14,15,16,17,44,45,46,47,48,49,50,51,52,53) AND wp_posts.ID NOT IN (
					SELECT object_id
					FROM wp_term_relationships
					WHERE term_taxonomy_id IN (18)
				) ) AND wp_posts.post_type = 'post' AND (wp_posts.post_status = 'publish') GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC LIMIT 0, 40\G

From what i understand it is generated by wp-blog-header.php

This is what I got from slow query log:

# Query 1: 0.02 QPS, 0.65x concurrency, ID 0xA13A8CDCEEA90AEA at byte 244013
# Scores: Apdex = 0.14 [1.0], V/M = 48.37
# Query_time sparkline: |      _^|
# Time range: 2012-04-30 14:40:37 to 2012-05-01 14:30:02
# Attribute    pct   total     min     max     avg     95%  stddev  median
# ============ === ======= ======= ======= ======= ======= ======= =======
# Count         36    1296
# Exec time     73  55923s      1s    249s     43s    107s     46s     17s
# Lock time     55   5167s       0    212s      4s      6s     25s       0
# Rows sent     44  49.11k       3      40   38.80   38.53    6.31   38.53
# Rows examine  47  54.33M  34.60k  51.62k  42.93k  51.46k   8.31k  34.83k
# Query size    49 597.58k     440     506  472.16  487.09      33  420.77
# String:
# Databases    *****
# Hosts        *****
# Users        *****
# Query_time distribution
#   1us
#  10us
# 100us
#   1ms
#  10ms
# 100ms
#    1s  ##########################################################
#  10s+  ################################################################
# Tables
#    SHOW TABLE STATUS FROM <code>MY-DB-NAME</code> LIKE 'wp_posts'\G
#    SHOW CREATE TABLE <code>MY-DB-NAME</code>.<code>wp_posts</code>\G
#    SHOW TABLE STATUS FROM <code>MY-DB-NAME</code> LIKE 'wp_term_relationships'\G
#    SHOW CREATE TABLE <code>MY-DB-NAME</code>.<code>wp_term_relationships</code>\G
# EXPLAIN /*!50100 PARTITIONS*/
SELECT   wp_posts.* FROM wp_posts  INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) WHERE 1=1  AND ( wp_term_relationships.term_taxonomy_id IN (2,43,6,7,8,9,10,11,12,13,14,15,16,17,44,45,46,47,48,49,50,51,52,53) AND wp_posts.ID NOT IN (
					SELECT object_id
					FROM wp_term_relationships
					WHERE term_taxonomy_id IN (18)
				) ) AND wp_posts.post_type = 'post' AND (wp_posts.post_status = 'publish') GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC LIMIT 0, 40\G

I’m new to all this, can anyone explane me what exactly this query does and how can I improve it.

Thanks
G.