SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fce523620bcc07e1fe6daefa7defc414b48a3c0a345214584e7321140fbdad5d' 
  AND token = 'HT7EDGATgtDQWX74YFr2b02/iimyY09VLMEKRpWKeAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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