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SELECT 
  a.modifier, 
  a.modifier_type, 
  IF(
    shared_option_variants.variant_id IS NOT NULL, 
    shared_option_variants.modifier, 
    a.modifier
  ) as modifier, 
  IF(
    shared_option_variants.variant_id IS NOT NULL, 
    shared_option_variants.modifier_type, 
    a.modifier_type
  ) as modifier_type, 
  a.variant_id 
FROM 
  cscart_product_option_variants a 
  LEFT JOIN cscart_ult_product_option_variants shared_option_variants ON shared_option_variants.variant_id = a.variant_id 
  AND shared_option_variants.company_id = 1 
WHERE 
  1 
  AND a.variant_id IN (
    218476, 225700, 220212, 237792, 225255, 
    225266, 225277, 225335, 225366, 237823, 
    221140
  )

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "shared_option_variants",
      "access_type": "system",
      "possible_keys": ["PRIMARY", "company_id"],
      "rows": 0,
      "filtered": 0,
      "const_row_not_found": true
    },
    "table": {
      "table_name": "a",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["variant_id"],
      "rows": 11,
      "filtered": 100,
      "attached_condition": "a.variant_id in (218476,225700,220212,237792,225255,225266,225277,225335,225366,237823,221140)"
    }
  }
}

Result

modifier	modifier_type	variant_id
0.000	A	218476
0.000	A	220212
0.000	A	221140
0.000	A	225255
0.000	A	225266
0.000	A	225277
0.000	A	225335
0.000	A	225366
0.000	A	225700
0.000	A	237792
0.000	A	237823