SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a513358748ed32eb65684dde97e04ea14954739a746337132fea6dd3e586a2b' 
  AND token = 'tNMuTDdI4sYk5QZ8ngBCKHGywVwcPmp34OH6MwjayDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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