SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb796929b2069dbbe02c92cb735195d6443cd2d738ad7d10f673666341c37da8' 
  AND token = 'AGtgzaWdkUVWqFuI3hLzeBXjrrVZ/JmhNRLfCyEug5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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