SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ca412ad32d43386ce317bd057905c8cf5e44da425ec2079432935175c63c27' 
  AND token = 'VmlaKT5Mebi5oIFAeDuYtN/YLGjLYfSdXuW6/U8Dwc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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