SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e9c71d2826edfb9827461d55882ae92b426cde3d66034e955503a5794c39501' 
  AND token = 'B4xXUqrzi9ZBgCc9vZQRaveL3FpncOIXzjhdcwwZkBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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