SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae9975cef24311efa1870984f2ed8d98c731f457c19aa7011b07cd796e9c7833' 
  AND token = 'KRXnlB+DzwmyKWSb+p+it9nn5GTi+lFbMRqKLWvF9X8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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