SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fe56c08d324fcff5b866c549de757b6d99871cd3fbf4a37a196fe1b18c8134d' 
  AND token = 'yXCFBGD+HPAqO7dwlBLqHiWi92UQz5trkKvSlAbc1M8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}