SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1b4d72efd914df228b5de2977ea5766057044818a2b644fb76781fc60998e8c' 
  AND token = 'wBzd/ttspC3Y5BL7VfLxEuj7pHkreESAsIfDyrZl1wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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