SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5883104a2f5ead2ffdf92fcd8692e868c1888b7c69555cfff9e1561f1ca9f003' 
  AND token = 'KfNruY/HD7jenKtWWlkSE2kWChq2GW7+gze8ARU9oVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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