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 (
    431448, 431258, 431266, 431299, 431413, 
    431449, 431477, 431485, 430777, 431499, 
    431307, 431347, 431366, 431348, 430709, 
    431388, 430774, 431221, 431476, 431363, 
    431375, 431228, 431265, 431418, 431206, 
    431317, 430779, 431404, 431445, 431486, 
    431179, 431491, 431321, 431400, 431473, 
    430710, 431277, 430668, 431209, 430670, 
    431257, 431293, 431379, 431370, 431374, 
    431443, 431256, 431320, 431286, 431390, 
    431397, 431462, 431389, 431268, 431070, 
    430783, 431433, 431306, 431398, 431432, 
    431255, 431305, 431493, 430763, 431386, 
    430775, 430784, 431444, 431254, 431490, 
    435512, 431016, 431417, 430967, 431399, 
    431272, 431484, 430776, 431371, 431416, 
    431318, 431216, 431319, 435513, 431173, 
    431461, 431271, 431372, 435515, 431373, 
    431269, 435514, 430729, 431267, 435516, 
    431270, 435517
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00227

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "135.97"
    },
    "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": 97,
      "rows_produced_per_join": 97,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "116.58",
        "eval_cost": "19.40",
        "prefix_cost": "135.98",
        "data_read_per_join": "662K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (431448,431258,431266,431299,431413,431449,431477,431485,430777,431499,431307,431347,431366,431348,430709,431388,430774,431221,431476,431363,431375,431228,431265,431418,431206,431317,430779,431404,431445,431486,431179,431491,431321,431400,431473,430710,431277,430668,431209,430670,431257,431293,431379,431370,431374,431443,431256,431320,431286,431390,431397,431462,431389,431268,431070,430783,431433,431306,431398,431432,431255,431305,431493,430763,431386,430775,430784,431444,431254,431490,435512,431016,431417,430967,431399,431272,431484,430776,431371,431416,431318,431216,431319,435513,431173,431461,431271,431372,435515,431373,431269,435514,430729,431267,435516,431270,435517)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}