SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '932c6cce99b80b6309aa35f065ca80dbd8c009b06a555fec587b99a85f09ef46' 
  AND token = 'TceVgWhOx8ZYGRDFe7vR68eCt8vsTilFrXRxEeejMgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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