SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a9a85a2ee9009a308c230431b99547fe92f0989c99983ebe02b9ddf1e431e04' 
  AND token = 'vuctOkbk8CzEaXf7JVO7C2q8FPFW22xzc3noU2djVD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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