SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a6d1acf395fb607ec414ec71733887e3df4e2c0157e6e7740685a6c03a10977' 
  AND token = 'upKbACAGL7B0YHvsW1oaZ5iDgDp+EWXuQHJhyjOqabg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}