SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efab62da37bf852467236aff3ed99817edf351277fa590b975b8247c4cb55d10' 
  AND token = 'TkswWGuvb6MbTNKbNO+DWN1jpVxXFCxnmhHxKhBqdlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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