SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cf0f902d7eeb6220dabbff884d9e71f757a764aa6a759d0975c54166be08ba1' 
  AND token = 'si3PtmxQdLJNiaZnMJAlikz4iP9NMR11Tmjhqv1gEMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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