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 = 'vi' 
WHERE 
  pfv.variant_id IN (
    70941, 70940, 70942, 70944, 70943, 70945, 
    70965, 70964, 70966, 70974, 70973, 
    70975, 74213, 74212, 74214, 74959, 
    74958, 74957, 74960, 76046, 76728, 
    76730, 76729, 78429, 78428, 78430, 
    78433, 78434, 79212, 79213, 79211, 
    79215, 79216, 79214, 79224, 79225, 
    79223, 81512, 81513, 81515, 82386, 
    82387, 82388, 82389, 82393, 82392, 
    82391, 82390, 82399, 82400, 82401, 
    82407, 82408, 82409, 82410, 82411, 
    82412, 83212, 83213, 85235, 85236, 
    85237, 86220, 86219, 86218
  )

Query time 0.01008

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": 65,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70941,70940,70942,70944,70943,70945,70965,70964,70966,70974,70973,70975,74213,74212,74214,74959,74958,74957,74960,76046,76728,76730,76729,78429,78428,78430,78433,78434,79212,79213,79211,79215,79216,79214,79224,79225,79223,81512,81513,81515,82386,82387,82388,82389,82393,82392,82391,82390,82399,82400,82401,82407,82408,82409,82410,82411,82412,83212,83213,85235,85236,85237,86220,86219,86218)"
        }
      },
      {
        "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 = 'vi'"
        }
      }
    ]
  }
}