SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '781e5affbfff056b6f5155637b34458fa275524fc18c778deab6861b8c593d84' 
  AND token = '4w2JJLZOv6xcWRhhbujhpzSlJMjKZT59nLe1S+0n95Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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