SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b2dc72c60f0638906d84cb5f2458af0bb51997be83f2c0db22000b694fc647d' 
  AND token = 'bBk+lxuVkZQu/mq3yHBYiKzrIzgBju+bj2R8BK1bB3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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