SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3efbe6d1d5a2238137cf5447ee348ee9f387866942361d8f402178f21ff49311' 
  AND token = '/5xYj2vHq7LjRYe25qqEftFe4XNCeFKTUzx4xNVvc1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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