SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '633ab6132644cdf44f755fd22e7a979632496c08cc22c3b292f53a7d0a1bd711' 
  AND token = 'K7YwIUnMc/0QSWYQUN9ybPtZVB0OqdVmy1LhDVW2ubE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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