SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca57b1be4916a943feaecc75c920493b49fe701ed8022bf41a49c2a267673dd3' 
  AND token = 'oFb76RImxHb0ax11OZqKq9SOmm/1ygZ3oRAMyNs5RZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}