SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    10343, 10345, 10346, 10347, 10348, 10349, 
    10350, 10351, 10352, 10353, 10354, 
    10355, 10356, 10357, 10358, 10359, 
    10360, 10361, 10363, 10364
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00356

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 20,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (10343,10345,10346,10347,10348,10349,10350,10351,10352,10353,10354,10355,10356,10357,10358,10359,10360,10361,10363,10364) and cscart_product_descriptions.lang_code = 'ru'"
    }
  }
}