Improving query performance from mysql slow log query - mysql

Question

We are using Prestashop as an e-commerce application and for the mobile application we used the same database and Prestashop architecture and almost using the same queries from core PrestaShop.
For some of the queries that we are using in our NODE Js API give us RDS (MySQL) CPU spike up to 100% when the traffic spikes up.
RDS configuration: db.m4.xlarg,4vCPU, 16 GB RAM
Slow Query (This query only appears in slow query logs when traffic is high) :
EXPLAIN SELECT t1.id_product,
t1.position,
t1.price,
t1.quantity,
t1.reserve_stock,
t1.name,
t1.link_rewrite hyphen_name,
t1.id_category_default,
t1.id_sub_category,
t1.is_back_in_stock,
(SELECT link_rewrite FROM pml_category_lang WHERE id_category = 36 AND id_shop = 1 AND id_lang = 1 LIMIT 1) category_link_rewrite,
CONCAT('[', t1.images, ']') images,
t3.reduction,
t3.reduction_type,
IF(t3.reduction,
IF(t3.reduction_type = 'percentage', ROUND((t1.price - (t3.reduction * t1.price))),
ROUND(t1.price - t3.reduction)),
t1.price) discounted_price
FROM
(SELECT ps.id_product, ps.id_category_default, ps.is_back_in_stock, cp.position, ROUND ((7/100) * ps.price * 1 + ps.price * 1) price,
sa.quantity, sa.reserve_stock, pl.name, p.date_add, pl.link_rewrite,
(SELECT pml_category.id_category FROM pml_category
LEFT JOIN pml_category_product ON pml_category_product.id_category = pml_category.id_category
AND pml_category_product.id_shop = 1
WHERE id_parent = 36 AND pml_category_product.id_category IS NOT NULL AND pml_category_product.id_product = cp.id_product LIMIT 1) AS id_sub_category,
GROUP_CONCAT(DISTINCT CONCAT('{"id_image":', i.id_image, ',', '"position":', i.position, ',', '"cover":', ims.cover, '}')) images
FROM pml_category_product cp
JOIN pml_product_shop ps
ON cp.id_product = ps.id_product AND cp.id_shop = ps.id_shop
JOIN pml_product p
ON p.id_product = cp.id_product
AND p.id_category_default = 36
JOIN pml_stock_available sa
ON cp.id_product = sa.id_product AND cp.id_shop = sa.id_shop AND sa.id_product_attribute = 0 AND sa.quantity > 0
JOIN pml_product_lang pl
ON cp.id_product = pl.id_product AND cp.id_shop = pl.id_shop AND pl.id_lang = 1
JOIN pml_image i
ON cp.id_product = i.id_product
JOIN pml_image_shop ims
ON ims.id_image = i.id_image AND ims.id_shop = 1
WHERE ps.id_shop = 1
AND ps.active = 1 AND i.smartly !=1
AND ps.visibility = 'both'
GROUP BY cp.id_product) t1 join pml_pomelo_rank pr on t1.id_product = pr.id_product and pr.id_shop = 1 and (pr.alltime_regular_cr > 2 or pr.alltime_qty_sold > 100) and pr.id_product != 14930 and pr.id_product not in (select id_product_2 from pml_accessory where id_product_1 = 14930)
LEFT JOIN
(SELECT t2.* FROM
(SELECT id_product, id_specific_price_rule, reduction, reduction_type, `from`, `to`
FROM pml_specific_price
WHERE id_shop IN (0, 1) and id_currency IN (0,1)
AND ((`from` = '0000-00-00 00:00:00' OR '2017-08-15 13:15:33' >= `from`) AND (`to` = '0000-00-00 00:00:00' OR '2017-08-15 13:15:33' <= `to`))
ORDER BY id_product ASC, id_specific_price_rule ASC) t2
GROUP BY t2.id_product) t3
ON t1.id_product = t3.id_product ORDER BY rand() LIMIT 0, 4;
Current we are trying to find if it would be good to increase RDS infrastructure size or Queries like this needs improvements.
Note: this is exactly the same query that Prestashop core uses for category page
any suggestion or help regarding query optimization or infrastructure RDS (config) optimization for such queries would be helpful.
RDS GRAPH: