SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc716f9b6312cf6522447c30e5f70be275e1aac70c6f5cc34b40752766902374' 
  AND token = 'UzKRaQrPqSnrfdc8Osvei2Okgw4SfGJd3r3COVeA9tg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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