SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efa9284607279cb4f5fae471f675e182c03652814ca4a78d9ad0e28076f13f68' 
  AND token = 'uPDJaN5rj3isPZU8AW1r65xOaxajw2vtCOj+uK3KmdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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