SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '440adaf176f2fc30988df0fb656a4779948dc8c8f86cd60d3f081b24c36c249a' 
  AND token = 'WH8iAjXzpes1ZlFE2lSnCn/oQBMEkYVucTH7KWJno1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}