SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cab7fe0a7c656e5285ef9b6cbd5bc1a064d1328c5d6b879fc37e7e9a5ae3cc98' 
  AND token = 'QRMmgsTcVoWs0oeHnncDZ0mbFEnbUBFOetP0e9ampHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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