SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  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 (
    46, 22715, 22716, 51496, 21567, 91, 50989, 
    47, 105, 48, 49, 92, 137, 88, 126, 31
  ) 
  AND cscart_product_descriptions.lang_code = 'kk'

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "11.21"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 16,
      "rows_produced_per_join": 16,
      "filtered": "100.00",
      "index_condition": "((`test_uchur_k`.`cscart_product_descriptions`.`product_id` in (46,22715,22716,51496,21567,91,50989,47,105,48,49,92,137,88,126,31)) and (`test_uchur_k`.`cscart_product_descriptions`.`lang_code` = 'kk'))",
      "cost_info": {
        "read_cost": "9.61",
        "eval_cost": "1.60",
        "prefix_cost": "11.21",
        "data_read_per_join": "73K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text",
        "unit_name"
      ]
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
31
46
47
48
49
88
91
92
105
126
137
21567
22715
22716 футболка, futbolka, спортивная, sportivnaya, uchur, учур, totem, тотем, animal, анимал, raven, равен, цв, cv, черный, chernyy
50989
51496 панама, panama, uchur, учур, safari, сафари, цв, cv, бежевый, bezhevyy