SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd51b661903150522b9c93d9f7f14048b1f9434304003a9b808100cbd3923eaf5' 
  AND token = 'TZP8bVuF6G49pxHVGWoN7Q/o2CyudRxoGmxh+KqpYgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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