SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d1f98b2bbbad7e841125e759e923354e82c75dc0db046c80364ba7346059fd' 
  AND token = 'lZgGUKasrI4BDw9gR097rwplu/lJpIh2cO+fuhTk0n8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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