SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3bb47e06e376f5c4d1d38af6af311f51edafc8640b06ade3b06403c4a79a322' 
  AND token = 'tjP/gJs3Gq88VaWfouJBm07Vp77m3hOlGHHwKpkOpTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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