SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e25dd6d6db54acaade1351fd3dc27a5a6b7aaa13ba0afc51f6ccd2467eb6e1b8' 
  AND token = 'TbokaUw4i7gncdMJETPnjXlmY8zrLl8SMWGbZZuLQvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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