SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bb460932a81458dffdb8ea02339e26bbf19326ce232f585ab637cef461fb312' 
  AND token = '5jTNoSuIFQfZN8bununbgHlI8bwhVQ+EK184tLBk2iQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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