SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '792bf86d9fffd6304b7a26047cffaa75b6325f6fe83331bbf5fafb559402dd00' 
  AND token = '6WVCFDlus7MxIByLkRY7HMQgB821GnOL+y0FVLWvzXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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