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, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    3354, 3308, 3397, 3841, 3212, 3928, 3660, 
    3828, 3518, 3918, 3400, 3232, 3740, 
    3743, 3741, 3440, 3441, 10078, 3768, 
    3747, 3406, 3827, 3738, 3403, 3443, 
    3737, 3655, 3658, 3769, 3745, 3767, 
    3950, 3659, 3766, 3739, 3444, 3785, 
    3442, 3787, 3770, 3447, 3793, 3450, 
    3772, 3795, 3788, 3439, 3446, 3794, 
    3948, 3449, 3871, 3786, 3867, 3951, 
    3949, 3881, 11629, 8597, 8280, 8443, 
    8596, 11632, 8405, 8584, 8588, 8437, 
    8515, 8542, 10446, 10492, 11623, 11624, 
    11625, 11626, 11627, 11628, 11631
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00187

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "55.23"
    },
    "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": 78,
      "rows_produced_per_join": 78,
      "filtered": "100.00",
      "index_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`product_id` in (3354,3308,3397,3841,3212,3928,3660,3828,3518,3918,3400,3232,3740,3743,3741,3440,3441,10078,3768,3747,3406,3827,3738,3403,3443,3737,3655,3658,3769,3745,3767,3950,3659,3766,3739,3444,3785,3442,3787,3770,3447,3793,3450,3772,3795,3788,3439,3446,3794,3948,3449,3871,3786,3867,3951,3949,3881,11629,8597,8280,8443,8596,11632,8405,8584,8588,8437,8515,8542,10446,10492,11623,11624,11625,11626,11627,11628,11631)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "47.43",
        "eval_cost": "7.80",
        "prefix_cost": "55.23",
        "data_read_per_join": "355K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "unit_name"
      ]
    }
  }
}