SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99fbebab001dc4bccc4ec589977ef67015b246102dd6c264dc344f96ae21f995' 
  AND token = 'gU6BjuqCFUyxXvYzOQyVuZdB74GtJA6Fg0aZPoqJflo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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