SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '463c263dbf346b81ef12e628107cad4e1f273468fc706315c039d41d4d0fa673' 
  AND token = '3SFUX9ynSGy+WZCmdCzNvtXflNA5lJ4RecsqHQFz+uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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