SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42e967542d58449f7fff6ab183561657e94d26e6f246f13c89b3334c27bd57ad' 
  AND token = 'SqdAwz6xAGCrOnNqiPYhq/2Qu1ekAyVU+ofmLsLueRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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