SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfde366cb01d38f22e78272eb5448396e8ef3df5397623ccd41a9c3f4ea64864' 
  AND token = 'gbCobkmD1OvImqvUwtPuRzM+DJghJGcYR9XtLso8zDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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