SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'en' 
WHERE 
  pfv.variant_id IN (
    68419, 68420, 70491, 70492, 71441, 71440, 
    71790, 71789, 71788, 71787, 71786, 
    72389, 72390, 73468, 73467, 73466, 
    73465, 73464, 73469, 73462, 73461, 
    73460, 73463, 73503, 73502, 73571, 
    73570, 73583, 73582, 74213, 74212, 
    74214, 74507, 74508, 74506, 74573, 
    74574, 74572, 76695, 76694, 76696, 
    77360, 77361, 77362, 82492, 82501, 
    82502, 82503, 82504, 82505, 82506, 
    82507, 82508, 82493, 82494, 82495, 
    82496, 82497, 82498, 82499, 82500, 
    82560, 82562, 82559, 82561, 86387, 
    86386, 86385, 87346, 87347, 87348, 
    87349, 87739, 87740, 87741, 87736, 
    87737, 87738
  )

Query time 0.01236

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 78,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68419,68420,70491,70492,71441,71440,71790,71789,71788,71787,71786,72389,72390,73468,73467,73466,73465,73464,73469,73462,73461,73460,73463,73503,73502,73571,73570,73583,73582,74213,74212,74214,74507,74508,74506,74573,74574,74572,76695,76694,76696,77360,77361,77362,82492,82501,82502,82503,82504,82505,82506,82507,82508,82493,82494,82495,82496,82497,82498,82499,82500,82560,82562,82559,82561,86387,86386,86385,87346,87347,87348,87349,87739,87740,87741,87736,87737,87738)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["dev_db.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "pfvd.lang_code = 'en'"
        }
      }
    ]
  }
}