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 (
    4651, 5190, 1580, 3324, 3495, 5253, 5387, 
    3321, 3327, 1667, 3932, 2090, 2277, 
    5843, 2278, 5969, 3338, 2400, 5814, 
    5251, 5831, 4239, 5751, 5740, 4191, 
    5839, 2179, 5813, 1629, 5205, 5266, 
    1666, 5024, 5262, 5282, 5565, 3332, 
    5275, 5264, 5825, 5924, 5283, 5838, 
    5268, 5738, 1630, 3494, 5274, 2183, 
    2237, 5273, 5291, 2087, 3491, 3930, 
    4233, 5927, 2239, 8813, 1843, 5182, 
    2092, 5267, 5279, 2176, 2238, 5269, 
    5280, 5017, 1671, 3801, 2091, 1845, 
    2089, 3498, 5286, 2276, 4475, 3506, 
    5211
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00164

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "56.65"
    },
    "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": 80,
      "rows_produced_per_join": 80,
      "filtered": "100.00",
      "index_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`product_id` in (4651,5190,1580,3324,3495,5253,5387,3321,3327,1667,3932,2090,2277,5843,2278,5969,3338,2400,5814,5251,5831,4239,5751,5740,4191,5839,2179,5813,1629,5205,5266,1666,5024,5262,5282,5565,3332,5275,5264,5825,5924,5283,5838,5268,5738,1630,3494,5274,2183,2237,5273,5291,2087,3491,3930,4233,5927,2239,8813,1843,5182,2092,5267,5279,2176,2238,5269,5280,5017,1671,3801,2091,1845,2089,3498,5286,2276,4475,3506,5211)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "48.65",
        "eval_cost": "8.00",
        "prefix_cost": "56.65",
        "data_read_per_join": "365K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "unit_name"
      ]
    }
  }
}