SELECT 
  SQL_CALC_FOUND_ROWS products.product_id, 
  descr1.product as product, 
  products.product_type, 
  products.parent_product_id 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'en' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
WHERE 
  1 
  AND prices.usergroup_id IN (0) 
  AND (
    (
      1 
      AND products.product_id IN (409)
    ) 
    AND prices.usergroup_id IN (0)
  ) 
GROUP BY 
  products.product_id 
ORDER BY 
  NULL asc

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "products",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "descr1",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "ref": ["const", "const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "prices",
      "access_type": "const",
      "possible_keys": ["product_id"],
      "key": "product_id",
      "key_length": "9",
      "used_key_parts": ["product_id", "lower_limit", "usergroup_id"],
      "ref": ["const", "const", "const"],
      "rows": 1,
      "filtered": 100,
      "using_index": true
    },
    "table": {
      "table_name": "products_categories",
      "access_type": "ref",
      "possible_keys": ["PRIMARY", "pt"],
      "key": "pt",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["category_id"],
      "ref": ["herbaria_cscart_4_18.products_categories.category_id"],
      "rows": 1,
      "filtered": 100,
      "using_index": true
    }
  }
}