SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d5e4c899f680161c0015dffe369c0a9409c7ae2ec69f3ae3837b848244d215b' 
  AND token = '3QgyzgiaX0WnV0SgHofAeLqliIcxtYA1yprgqnLcXFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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