SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e13d90d1a624031677a80ab1f6302ba26ce42adaa75b0abd7d01468fad024430' 
  AND token = 'MbG85WCLsTy3xKuo/dAf3Mfk5dFNemaM3HNFlr83yG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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