SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef81175df4f13be2d85ed85130e7aa94529aa6d2bef15114e9732a270c16a235' 
  AND token = '3hYs9a4OJOCMtHYL9XpXvkjCDEvpvQIqK+udne5hPGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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