SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd244cb4f1f2f1837b3796902fb38366f95b59c72b830f1cf36e4a4459452c476' 
  AND token = 'mdeIgIzxKcU5nB8+mgxwCMVdpsQSVKRY83XdJzhQlzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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