SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c10021c452384df088e0e20c7ba906a674cde457fb31f7f2f0a87009c6cce05f' 
  AND token = 'FFWhrKDAJTA4t7ARgGyVKHQpUXhGRhWnbhllBihMmIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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