SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '673fb800c1a6c264811aaca016e62102ac05387d025961c3b545dbdf6bbd437d' 
  AND token = 'D5dfder2jEGOjl0y1LkOBcEKixZSSAqUp4ZSbrg35KQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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