SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f6caf4b9cf9b85263f8220015cc440fe4a423bdad156307ce28c889a9e22ce8' 
  AND token = 'hPLqCl/HJpDqYBhYnhjqWwix7p4/1lfCgjXISNMQHCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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