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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    85571, 85573, 85574, 91877, 91878, 91879, 
    91880, 91881, 91882, 91883, 85555, 
    85594, 85564, 90025, 85575, 86889, 
    86895, 82359, 87888, 91844, 92185, 
    92382, 85561, 91856, 82370, 86893, 
    85553, 85559, 92172, 92358, 92359, 
    92360, 92361, 92362, 92363, 92364, 
    85560, 85566, 85641, 89988, 91848, 
    91888, 85569, 91876, 85545, 92357, 
    84237, 85548
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00127

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (85571,85573,85574,91877,91878,91879,91880,91881,91882,91883,85555,85594,85564,90025,85575,86889,86895,82359,87888,91844,92185,92382,85561,91856,82370,86893,85553,85559,92172,92358,92359,92360,92361,92362,92363,92364,85560,85566,85641,89988,91848,91888,85569,91876,85545,92357,84237,85548)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}