SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daf7c2616e72eff6cc14bba0c46484d79a473b0f6000bbfbee4f80e13670bc77' 
  AND token = 'mf8+FGrSUPXUmbO0NEd2UpEhm9ovNrvl4vivdNJXAso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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