SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6458a991c682605c6c79b57e5d4e683c1f8c7dff63a83cd74f79ddad03595b52' 
  AND token = 'U2z/Rq6e2X2GzQqluUCqy0cUF6IuKHOHSPQHygVlPdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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