SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3700a603c97ec49ce5eb4b04b384fcebee296f433f24c34570136a2bdaadf3f0' 
  AND token = 'z3/IXGrdJYIrXfSx15eEdOkPgqmtKxxPzhDXJiuRAhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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