SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '519faafc7fae71b2289b521a4342016c698380584a043f7f5393c5d62dd9734b' 
  AND token = 'rFooUAQhw/kUchiqw5WfNGroHXzmtNtgWc6lhNshSBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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