MySQL range query is slow - mysql

Question

I have read different links like http://goo.gl/1nr3s2, http://goo.gl/gv4Vlc and other stackoverflow questions, but none of them help me with this problem.
This problem interacts with multiple tables, but the EXPLAIN method help me identify range is the main problem with the query.
First I need to explain that I have this table with this sample data (I will not use ids in any table to simplify the process)
+-------+----------+----------------+--------------+---------------+----------------+
| marca | submarca | modelo_inicial | modelo_final | motor | texto_articulo |
+-------+----------+----------------+--------------+---------------+----------------+
| Buick | Century | 1993 | 1996 | 4 Cil 2.2 Lts | BE1254AG4 |
| Buick | Century | 1993 | 1996 | 4 Cil 2.2 Lts | 854G4 |
+-------+----------+----------------+--------------+---------------+----------------+
This table has more than 1.5 Million rows and I have created a index that integrates initial_year and end_year in one and also initial_year has an index and end_year has another index independently like this structure.
CREATE TABLE `general` (
`id_general` int(11) NOT NULL AUTO_INCREMENT,
`id_marca_submarca` int(11) NOT NULL,
`id_modelo_inicial` int(11) NOT NULL,
`id_modelo_final` int(11) NOT NULL,
`id_motor` int(11) NOT NULL,
`id_articulo` int(11) NOT NULL,
PRIMARY KEY (`id_general`),
KEY `fk_general_articulo` (`id_articulo`),
KEY `modelo_inicial_final` (`id_modelo_inicial`,`id_modelo_final`),
KEY `indice_motor` (`id_motor`),
KEY `indice_marca_submarca` (`id_marca_submarca`),
KEY `indice_modelo_inicial` (`id_modelo_inicial`),
KEY `indice_modelo_final` (`id_modelo_final`),
CONSTRAINT `fk_general_articulo` FOREIGN KEY (`id_articulo`) REFERENCES `articulo` (`id_articulo`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=1191853 DEFAULT CHARSET=utf8
I have another table that contains different years like this sample data:
+---------+----------------+
| id_modelo | texto_modelo |
+-----------+--------------+
| 76 | 2014 |
| 75 | 2013 |
............................
| 1 | 1939 |
+-----------+--------------+
I created a query that contains subquery to obtain specific data but took a lot of time. I will put some queries I have tried but none of them have worked properly for me
SELECT DISTINCT M.texto_modelo
FROM general G
INNER JOIN parque_vehicular.modelo M ON G.id_modelo_inicial <= M.id_modelo AND G.id_modelo_final >= M.id_modelo
WHERE EXISTS
(
SELECT DISTINCT A.id_articulo
...subquery...
WHERE A.id_articulo = G.id_articulo AND AD.id_distribuidor = 1
)
ORDER BY M.texto_modelo DESC;
And this query took a lot of seconds, so I use EXPLAIN and report is:
This is another query I tried.
SELECT DISTINCT M.texto_modelo
FROM general G
INNER JOIN parque_vehicular_rigs.modelo M ON M.id_modelo BETWEEN G.id_modelo_inicial AND G.id_modelo_final
WHERE EXISTS
(
SELECT DISTINCT A.id_articulo
...subquery WHERE A.id_articulo = G.id_articulo AND AD.id_distribuidor = 1
)
ORDER BY M.texto_modelo DESC;

Answer 1

Some operations you could do to change the query plan:
OP1: Get rid of all the keys or indexes in table general.
OP2: Use SELECT 1 instead of SELECT DISTINCT A.id_articulo in the sub query in EXISTS.
Do these operations separately, compare the differences.