SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5718f7ceba00ae245439ae3414c4960edcca455b9290685700f9b6f29c35d11' 
  AND token = 'MrzJfWFfgGhGFATiDlxdqOwQDbAeb9zQ0hFPwbIXDzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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