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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.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (56, 57, 55) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00091

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.00429364,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_descriptions",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["product_id", "lang_code"],
          "loops": 1,
          "rows": 3,
          "cost": 0.00429364,
          "filtered": 100,
          "attached_condition": "cscart_product_descriptions.product_id in (56,57,55) and cscart_product_descriptions.lang_code = 'en'"
        }
      }
    ]
  }
}

Result

product_id	full_description	promo_text
55	<p>The PRS-D800 2-channel amplifier contains audiophile grade components that were carefully selected and design perfected to achieve highest audio quality.</p>	<p class="product-promo-text"><span class="product-promo-header">FREE US shipping over $100!</span><span class="product-promo-body">Orders within next 2 days will be shipped on Monday</span></p>
56	<p>From dramatic distinction to dramatic design, Pioneer's new GM-Series amplifiers are thrillers in every sense, pushing the limits of flexibility and functionality.<br /><br />The 4-channel GM-6500F delivers a whopping 760 watts max - plenty of juice to power your speakers. It's also got built-in low-pass/high-pass crossovers, speaker level inputs for easy connection to an OEM headunit and oversized power terminals.</p>	<p class="product-promo-text"><span class="product-promo-header">FREE US shipping over $100!</span><span class="product-promo-body">Orders within next 2 days will be shipped on Monday</span></p>
57	<p>Class-D amplifiers overcome the inefficiencies of traditional Class-A or AB amplifiers. Pioneer’s Class-D amps transform very little power into heat so a higher percentage of the power supply (67%) is transformed into the load. This results in a very compact amp which needs less input power to produce very high output power. The Class-D amplifier’s PWM (Pulse Width Modulator) modulates the original audio input signal with a triangulated signal wave which has a much higher fixed frequency. The result is a digital signal which contains both the input signal and a band of frequency components around the modulation frequency. A LPF (Low Pass Filter) then filters out the high frequency pulses and the resulting amplified output signal is then sent to the subwoofer and/or speakers.</p>	<p class="product-promo-text"><span class="product-promo-header">FREE US shipping over $100!</span><span class="product-promo-body">Orders within next 2 days will be shipped on Monday</span></p>