SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f1b9755ae83ca6e4e84139ea31a26d9f978cba1e03591162cec5ee215052a46' 
  AND token = 'V5SuCxyecX9tJqMq+po+HffrNOjMtVRmxbmjNez99WE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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