How can I optimize the MYSQL query related to regions - mysql

Question

Country table has around 2 records.
State table has around 50 records.
City table has around 6000 records.
Zipcode table has around 500000 records
Approximate exicution time to fetch data is around 12-15 minutes.
How can I optimize below query:
SELECT Country.id AS Country_id,
Country.country AS Country_country,
Country.countrycode AS Country_countrycode,
State.id AS State_id,
State.statecode AS State_statecode,
City.id AS City_id,
City.city AS City_city,
Zipcode.id AS Zipcode_id,
Zipcode.zipcode AS Zipcode_zipcode
FROM c_country Country
LEFT JOIN c_state State
ON Country.id = ( State.country_id )
LEFT JOIN c_city City
ON State.id = ( City.state_id )
LEFT JOIN c_zipcode Zipcode
ON City.id = ( Zipcode.city_id )
Below are the table structure:
CREATE TABLE `c_city` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`state_id` int(11) NOT NULL,
`city` varchar(256) NOT NULL,
`zone_id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7027 DEFAULT CHARSET=latin1;
CREATE TABLE `c_state` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`country_id` int(11) NOT NULL,
`state` varchar(256) NOT NULL,
`statecode` varchar(256) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=latin1;
CREATE TABLE `c_country` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`country` varchar(256) NOT NULL,
`countrycode` varchar(256) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;
CREATE TABLE `c_zipcode` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`city_id` int(11) NOT NULL,
`zipcode` varchar(256) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=539420 DEFAULT CHARSET=latin1;
Below is the screenshot of EXPLAIN SELECT:

Answer 1

for try to improve performanbce you could add index for
table c_zipcode column city_id
table c_city column state_id
table c_state column country_id
or for resolve too all the columns values using the index
table c_zipcode column city_id, zipcode
table c_city column state_id, city
table c_state column country_id , statecode

Answer 2

I think your query is very slow because there is some index missing. You didn't declare any Foreign Key, in mysql InnoDB, Foreign Key are important because they are warranty for the data integrity but MySQL create automatically index on this foreign keys too.
a link to explain : https://dba.stackexchange.com/questions/105469/performance-impact-of-adding-a-foreign-key-to-a-1m-rows-table
You have to alter the tables to add foreign keys :
ALTER TABLE c_city ADD CONSTRAINT fk_state_id FOREIGN KEY (state_id) REFERENCES c_state(id);
ALTER TABLE c_state ADD CONSTRAINT fk_country_id FOREIGN KEY (country_id) REFERENCES c_country(id);
ALTER TABLE c_zipcode ADD CONSTRAINT fk_city_id FOREIGN KEY (city_id) REFERENCES c_city (id);