SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcb5acddec6a81263eacb78d1fd5c5de7aa20d74def2d976684f4819c40fb78c' 
  AND token = 'WgmRRIo9FNTAzQzGueQEMNM54fZJX0eD6DRUqdDNvP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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