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 (
    51567, 51565, 51564, 139, 129, 51566, 
    51301, 51, 50, 51497, 51498, 53, 22713, 
    21, 22714, 22712, 46, 22715, 22716, 
    51496, 21567, 91, 50989, 47, 105, 48, 
    49, 92, 137, 88, 126, 31, 51358, 115, 
    37, 11, 140, 41, 30, 90, 38, 124, 81, 56, 
    135, 82, 116, 117, 125, 106, 39, 193, 
    65, 40, 22710, 22711, 17, 57, 122, 58, 
    5, 22, 18, 27
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00106

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "44.81"
    },
    "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": 64,
      "rows_produced_per_join": 64,
      "filtered": "100.00",
      "index_condition": "((`test_uchur_k`.`cscart_product_descriptions`.`product_id` in (51567,51565,51564,139,129,51566,51301,51,50,51497,51498,53,22713,21,22714,22712,46,22715,22716,51496,21567,91,50989,47,105,48,49,92,137,88,126,31,51358,115,37,11,140,41,30,90,38,124,81,56,135,82,116,117,125,106,39,193,65,40,22710,22711,17,57,122,58,5,22,18,27)) and (`test_uchur_k`.`cscart_product_descriptions`.`lang_code` = 'ru'))",
      "cost_info": {
        "read_cost": "38.41",
        "eval_cost": "6.40",
        "prefix_cost": "44.81",
        "data_read_per_join": "292K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text",
        "unit_name"
      ]
    }
  }
}