Low Stock Amount Query blocking server

Hello,

We are having problems with our WooCommerce web shop. It was working fine for almost a year now, but today some SQL queries just get stuck and not processed, causing all 32 cpu cores to be used up.

The query in question is:

SELECT SQL_CALC_FOUND_ROWS  wp_posts.*, low_stock_amount_meta.meta_value AS low_stock_amount, MAX( product_lookup.date_created ) AS last_order_date FROM wp_posts  LEFT JOIN wp_wc_product_meta_lookup wc_product_meta_lookup ON wp_posts.ID = wc_product_meta_lookup.product_id  LEFT JOIN wp_postmeta AS low_stock_amount_meta ON wp_posts.ID = low_stock_amount_meta.post_id AND low_stock_amount_meta.meta_key = '_low_stock_amount'  LEFT JOIN wp_wc_order_product_lookup product_lookup ON wp_posts.ID = CASE
				WHEN wp_posts.post_type = 'product' THEN product_lookup.product_id
				WHEN wp_posts.post_type = 'product_variation' THEN product_lookup.variation_id
			END WHERE 1=1  AND wp_posts.post_type IN ('product', 'product_variation') AND ((wp_posts.post_status = 'publish'))
			AND wc_product_meta_lookup.stock_quantity IS NOT NULL
			AND wc_product_meta_lookup.stock_status IN('instock','outofstock')
			AND (
				(
					low_stock_amount_meta.meta_value > ''
					AND wc_product_meta_lookup.stock_quantity <= CAST(low_stock_amount_meta.meta_value AS SIGNED)
				)
				OR (
					(
						low_stock_amount_meta.meta_value IS NULL OR low_stock_amount_meta.meta_value <= ''
					)
					AND wc_product_meta_lookup.stock_quantity <= 2
				)
			) GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC, wp_posts.ID DESC LIMIT 0, 1

We have no clue why this happens. And it never happened before.