SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b189a3287b914878affc13f3ad32fde85587e3726bdcfffce0481e08fea243df' 
  AND token = 'UKBH9yG8usMLTWrwo5j/KfwROd7IOEiL5NHsIbQl4rw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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