SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fe3f9927425fab4d5c77b81174e11c26fa6667af9f18b9a64375638890082d4' 
  AND token = 'nvK1yKCdmxwNoXP2x4XMP2eMaXFr9EhWYTlz2MXwTbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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