SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73a5b61910776b415a066245deab348978f823ef2c50d6230425e4305ba435ea' 
  AND token = '1b3G6xyfq6izW424zio5k0GjxkpxmOFzqxSjdsiLPFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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