SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65e28c30f155c1d68de82bf4dfc3ec66024970de9911d4b73308a616d4917914' 
  AND token = 'UvqRckNo29EdtHlTbWciXRDhkoYBojnYeH6akvCkbno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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