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 (
    101479, 101480, 101481, 101482, 101483, 
    101484, 101485, 101486, 101487, 101488, 
    101489, 101490, 101491, 101492, 101493, 
    101494, 101495, 101496, 101497, 101498, 
    101499, 101500, 101501, 101502, 101503, 
    101504, 101505, 101506, 101507, 101508, 
    101626, 101660, 101661, 101662, 101663, 
    101664, 101665, 101666, 101667, 101668, 
    101671, 101746, 101747, 101748, 101749, 
    101750, 101751, 101752
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00118

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 (101479,101480,101481,101482,101483,101484,101485,101486,101487,101488,101489,101490,101491,101492,101493,101494,101495,101496,101497,101498,101499,101500,101501,101502,101503,101504,101505,101506,101507,101508,101626,101660,101661,101662,101663,101664,101665,101666,101667,101668,101671,101746,101747,101748,101749,101750,101751,101752)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}