SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f430e36bcbb136cbb24a04757877f074bb46f447c52d376b55237fff7cca89a5' 
  AND token = 'l9c1FcHUzVdw5UenLS0vWSEkeTzd1tPihVhNi7roGZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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