Partitioned view performance

How come MySQL is not using the indexes when querying the view? Each one of these tables have about 600,000,000 records.
Here are the tables definition

CREATE TABLE tbl2005 (
Col1 datetime,
Col2 varchar(12),
Col3 char(2));
CREATE INDEX idx_tbl2005_Col1_Col2 ON tbl2005 (Col1, Col2);

CREATE TABLE tbl2006 (
Col1 datetime,
Col2 varchar(12),
Col3 char(2));
CREATE INDEX idx_tbl2006_Col1_Col2 ON tbl2006 (Col1, Col2);

CREATE VIEW vwMyView
AS
SELECT Col1,
Col2
FROM tbl2005
UNION
SELECT Col1,
Col2
FROM tbl2006;

SELECT *
FROM vmMyView
WHERE Col1 = ‘20050110’;

This SELECT statement will take forever.

But if I run from the query window the DML specified in the view with the WHERE clause, I get the results inmediately - see below.
SELECT Col1,
Col2
FROM tbl2005
WHERE Col1 = ‘20050110’
UNION
SELECT Col1,
Col2
FROM tbl2006
WHERE Col1 = ‘20050110’;

Can you please show EXPLAIN for both query using view and direct query?