SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0d40f9d2fa7708124ce1c78a319c25f921a880cc045c01ec3ac5b172be786fa' 
  AND token = 'dMrz7PlSrPyzaayZ7WpQsC/BP5hrxaUDq9waEN5MvAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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