SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cbb178176dbb1804b8655bd46e191f947a084ebd5645f8facdb0e2919fb864a' 
  AND token = 'Cb67y37lwbQHDIdtrPh7y+mzD0V8MB8L9b+7QowXjzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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