SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '562948681c38047aae9b700133c8d193aebf210cdfcb65193023b34917205444' 
  AND token = 'eSOpBs+KHbXtWSE93jiWqA8v0v62AxV0h42zrkgx4Lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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