SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b54473db183399a0f3fd69bb043d1e0408531ae4a3ade0dfc21d10fbce706796' 
  AND token = 'M8uYwKOi1aieEpXrgIhCP9U9r/nNO/I69biHIO9uKTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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