SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a28eabd6032a8d21c3a65bd49f91cd34835ad1c0aea6dff6b4848092691e16f8' 
  AND token = 'YG7dxFNq8B+JqhjkW2gzavrC9RS0+c4l3BOpF9KrF5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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