SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc917bfe047652031f242f824d8f4aecf540bb11052294a5e705892f5d35b62c' 
  AND token = 'zCj37uftla/YnkatlRVzJxw7P7bEtXoqTqRhr+17ILg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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