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 (
    388361, 388366, 388370, 388451, 389024, 
    415307, 388526, 388500, 388585, 388819, 
    389114, 388800, 388517, 435240, 388602, 
    391758, 389105, 435259, 389520, 435241, 
    388365, 435261, 435239, 389501, 435236, 
    388599, 389798, 435234, 389212, 388532, 
    429100, 388790, 389785, 388369, 414934, 
    389055, 389773, 388360, 389505, 435237, 
    388375, 429409, 389562, 429099, 388584, 
    389484, 389219, 434581, 388376, 389116, 
    388603, 389792, 429098, 389767, 389788, 
    389789, 389783, 389047, 389631, 434580, 
    388791, 388380, 414932, 389636, 389468, 
    389486, 389784, 389103, 388556, 388503, 
    388865, 434575, 428686, 388546, 388408, 
    414933, 391742, 389088, 389519, 389635, 
    388537, 389766, 388772, 388799, 389781, 
    389787, 389790, 434579, 388607, 435309, 
    391757, 389027, 388555, 389506, 388936, 
    389093, 391743, 389786, 389782, 389772
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00257

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 (388361,388366,388370,388451,389024,415307,388526,388500,388585,388819,389114,388800,388517,435240,388602,391758,389105,435259,389520,435241,388365,435261,435239,389501,435236,388599,389798,435234,389212,388532,429100,388790,389785,388369,414934,389055,389773,388360,389505,435237,388375,429409,389562,429099,388584,389484,389219,434581,388376,389116,388603,389792,429098,389767,389788,389789,389783,389047,389631,434580,388791,388380,414932,389636,389468,389486,389784,389103,388556,388503,388865,434575,428686,388546,388408,414933,391742,389088,389519,389635,388537,389766,388772,388799,389781,389787,389790,434579,388607,435309,391757,389027,388555,389506,388936,389093,391743,389786,389782,389772)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}