SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5acf9dc7dd1fc5e91b79faf0f26b002c23cfcfb7366603e7ab5d62fcb5c4a516' 
  AND token = '7LHFRrj+TbmXka8upHfYQRi387kUpRmwkgqMKOEaf0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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