SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cbd1e02f2fc903924bde3877f719ba92847ef9f5e775c79e364fa57c60764ba' 
  AND token = 'IwvgmwGTmnI74eXBA2wqTCBkZQO+5zPX4hLf9j0fRiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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