SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81d27106852cea648db8cb849a789b8f7e4d71a1fc565ae5f76722872ac1dd4c' 
  AND token = 'oPgJ+9Zz6BilQCw4qu65d+LHYG8VzqwIBKXnHkWJPlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}