SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19478be391dfc7afb75cb73f5875517133ae999bb923cd3a2e8be7b704ee41c0' 
  AND token = 'vGTi0Ua81HhUXXuqGZN3ehqFyiwiu8wqUubVKk1RAz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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