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 (
    430983, 431434, 430642, 430954, 431166, 
    431260, 431380, 431409, 431004, 431105, 
    431304, 431346, 431480, 430963, 431287, 
    430781, 430964, 430966, 431002, 431071, 
    431458, 430754, 430759, 430814, 431015, 
    431324, 430798, 431217, 431079, 431352, 
    431408, 431452, 431453, 430669, 430750, 
    430944, 431273, 431362, 431407, 431481, 
    431188, 431222, 431394, 430700, 430705, 
    430727, 430938, 431001, 430978, 430985, 
    431009, 431057, 431208, 431241, 431335, 
    431447, 430699, 430752, 430757, 430773, 
    430942, 430973, 431210, 431383, 431502, 
    431292, 431427, 431488, 430719, 431017, 
    431236, 431330, 431040, 431466, 430630, 
    430929, 430943, 431227, 431235, 430632, 
    430693, 431263, 431482, 430955, 431018, 
    430971, 431069, 431364, 431378, 431415, 
    431302, 431361, 431421, 430717, 430736, 
    431281, 431385, 430725, 431285, 431223
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00426

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "140.18"
    },
    "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": 100,
      "rows_produced_per_join": 100,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "120.18",
        "eval_cost": "20.00",
        "prefix_cost": "140.18",
        "data_read_per_join": "682K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (430983,431434,430642,430954,431166,431260,431380,431409,431004,431105,431304,431346,431480,430963,431287,430781,430964,430966,431002,431071,431458,430754,430759,430814,431015,431324,430798,431217,431079,431352,431408,431452,431453,430669,430750,430944,431273,431362,431407,431481,431188,431222,431394,430700,430705,430727,430938,431001,430978,430985,431009,431057,431208,431241,431335,431447,430699,430752,430757,430773,430942,430973,431210,431383,431502,431292,431427,431488,430719,431017,431236,431330,431040,431466,430630,430929,430943,431227,431235,430632,430693,431263,431482,430955,431018,430971,431069,431364,431378,431415,431302,431361,431421,430717,430736,431281,431385,430725,431285,431223)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}