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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 (4137, 4139, 4140) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00021

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 (4137,4139,4140)",
      "attached_condition": "cscart_product_descriptions.lang_code = 'en'"
    }
  }
}

Result

product_id	full_description	search_words
4137	<p>This compact microphone has a revolutionary windporting feature that helps lessen background noise from high winds and other severe weather conditions. Audio can pass through the speaker grill even when the microphone port is blocked by water. The coiled cord allows talking and listening without removal from belt or case. Includes Push-to-talk switch, swivel clip and quick disconnect latch. </p>	CP110 Speaker Mic, CP185 Speaker Mic, CP200 Speaker Mic, CP200d Speaker Mic, CP200XLS Speaker Microphones
4139	<p>These Remote Speaker Microphones include a six foot coiled cord assembly, swivel clip and quick disconnect latch. The windporting feature dramatically lessens background noise from high winds and other severe weather conditions. The IP57 submersible model was tested at one meter for 30 minutes. Intrinsically Safe when used with the PR400. </p><p>Alternative to the PMMN4013A.</p>	CP110 Speaker Mic, CP185 Speaker Mic, CP200 Speaker Mic, CP200d Speaker Mic, CP200XLS Speaker Microphones, CP200, CP200d, CP100, CP100d, CP185, CP200XLS, CP110, CP-200, CP-200d, CP-100, CP-100d
4140	<p>Motorola PMMN4077 – Remote Speaker Microphone - Mag One </p>	BPR20 Speaker Mic, BPR40 Speaker Microphones, PMMN-4077, PMMN-4077A, PMMN4077-A, BPR40d, BPR40d speaker mic, BPR40d mic, BPR40 mic, BPR 40, BPR 40 speaker mic, BPR 40 mic, CP100d speaker mic, CP100d RSM, CP100d mic, CP100d compact mic, CP185 speaker mic, CP185 compact mic, CP185 RSM