SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddbc9df47c5fca4a2a6c9264f2c92852cd87727b81f67ee0008f6be5a9138952' 
  AND token = 'paUgGtbLvq9FD/gs7CJD2WtTjMqABz/XL/Z65+XkxdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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