SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cadccf4c46a244f37766a8528b35706607a1ffd260948b9b7aeccde1a8158a1' 
  AND token = '6qFQf6ZtaouFnh/LEj7xh1+MjDY7LXfZQER4MQUZb8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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