SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '715910db6a6626a14d822f721b07486b99525d2c452bf8f183d8783517a8b31e' 
  AND token = '4WHNYzGiZEJgCra8wfuZywVqhrJEC2/2heefViAhGeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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