SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cddfc12fedebac2b00055078716eb44d267a6718adef65ae1e114d7bb6f0eb62' 
  AND token = 'pRnzjfVEI76V1VE84nZGSkyC70jlRQMvd3K7p0GbclY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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