SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '759bea63099d04592dedb7099732b9367f84da1b2e637d522c1fc7c748646711' 
  AND token = '5h4poqGoP34Q0BKrJGZ54mA0gdrAEEfRl8pTYOkuDnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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