SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a46fc8a7850e9537e69480f1ad10d9eebae78d2a255c265ca1997bf152194421' 
  AND token = 'HdRklDic1GxpAXfjVRM+7NlMKn6jYD4pYyMtxs4Jvis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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