SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ccc30e1dc4093f945a6fd41430d899207d1dfce8c57a31eb1b3823be5e42000' 
  AND token = 'MWdFkO/X8ZXaF+BmFloqoLy5NxCdeOtHyQSfsdHmXLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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