SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5850d073b30e22dfcf3095ccc1f2ae69aca75f4ad984d40572c28fce0300d8db' 
  AND token = 'AfyMNHmXoqmJeQimkrlQo7czS5zxGtuk8UsCUhbAfZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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