SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328d18d746849930137ea54e1edcbb690ed067bc189927c686222b5b1fd88e1d' 
  AND token = '0LC7jw7N0jtHt8Rj+kwUrvCETKXn2tr6SZYp83rcyxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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