SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b9a43ab09d2945fc4eccfb96baa1129de9068212cb12404a4ea6a6bc020a53a' 
  AND token = 'BzPQrZjYasyuaieoae7bFG2sd0T3lpVSddGDrrBqIYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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