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SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '', 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (4059, 4973, 4948) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 3,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (4059,4973,4948)",
      "attached_condition": "cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id	short_description	full_description	search_words
4059		<p>The PMLN5048 has been replaced with the PMPN4171A. This Mag One rapid-rate charger is compatible with the BR20, BR40 and BPR40d radios and includes base, power supply and AC cord. </p>	BPR20 Charger, BPR40 Charger, BPR40d Charger, BPR 20, BPR 40, BPR 40d
4948		<p>Compatible with BPR40 and BPR20 portable radios. (Using PMNN4071 and PMNN4075 batteries)</p><p><span data-bind="widgetLocaleText: 'dimensions'">Dimensions</span> (<span data-bind="text: msiDimensionUOM.value ? msiDimensionUOM.value : 'IN-Inch'">IN-Inch</span>): <span data-bind="text: value">3</span> <span data-bind="widgetLocaleText: 'width'">(W)</span> <span data-bind="text: value">17</span> <span data-bind="widgetLocaleText: 'height'">(H)</span> <span data-bind="text: value">6.5</span> <span data-bind="widgetLocaleText: 'length'">(L)</span><br></p>
4973	<p>(includes PMLN5048_R and PMNN4075)</p>