SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56e6ac5f947dfd4a08674b5c025892ffa4d8891454d66ed22e899924319f5904' 
  AND token = 'zZjTPpUzllGOPZECnhcVFIbRzQvjKArvO1VXIL+Q5Y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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