Home page query for new reviews does a full table scan

[dfabulich]

Edit dbconnect.php and set logging_level = 2 in mysql_query, then refresh the home page logged out.

We're doing this query, which does a full table scan of the reviews table.

MariaDB [ifdb]> explain select
    ->   reviews.id as id, gameid, summary, review, rating, special,
    ->   games.title as title,
    ->   users.id as userid, users.name as username,
    ->   greatest(reviews.createdate,
    ->            ifnull(reviews.embargodate, '0000-00-00')) as d,
    ->   date_format(greatest(reviews.createdate,
    ->               ifnull(reviews.embargodate, '0000-00-00')),
    ->               '%M %e, %Y') as fmtdate,
    ->   (games.coverart is not null) as hasart,
    ->   games.pagevsn,
    ->   (users.picture is not null) as haspic,
    ->   games.flags
    -> from
    ->   reviews
    ->   join games
    ->   join users
    ->   left outer join specialreviewers on specialreviewers.id = special
    -> where
    ->   games.id = reviews.gameid
    ->   and users.id = reviews.userid
    ->   and reviews.review is not null
    ->   and ifnull(now() >= reviews.embargodate, 1)
    ->   and ifnull(specialreviewers.code, '') <> 'external'
    ->   and users.sandbox in (0)
    ->   and 1
    ->
    -> order by d desc, id desc
    -> limit 8;

+------+-------------+------------------+--------+-------------------------+---------+---------+----------------------+-------+-----------------------------+
| id   | select_type | table            | type   | possible_keys           | key     | key_len | ref                  | rows  | Extra                       |
+------+-------------+------------------+--------+-------------------------+---------+---------+----------------------+-------+-----------------------------+
|    1 | SIMPLE      | reviews          | ALL    | userid,gameid,user_game | NULL    | NULL    | NULL                 | 73088 | Using where; Using filesort |
|    1 | SIMPLE      | games            | eq_ref | PRIMARY                 | PRIMARY | 130     | ifdb.reviews.gameid  | 1     |                             |
|    1 | SIMPLE      | users            | eq_ref | PRIMARY                 | PRIMARY | 130     | ifdb.reviews.userid  | 1     | Using where                 |
|    1 | SIMPLE      | specialreviewers | eq_ref | PRIMARY                 | PRIMARY | 4       | ifdb.reviews.special | 1     | Using where                 |
+------+-------------+------------------+--------+-------------------------+---------+---------+----------------------+-------+-----------------------------+