SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da09a6d123b089499c6751ff8ecf054c24ada974a8095357d6c56093ddaeb9c' 
  AND token = 'XkYg/46S4kvepAQPQ4IaTTfa5VIz+oTHf8nV8MYOWHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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