SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46e956874a6be75bb42ea5f5a801790f5f3d9b1b9e99d5bca0be01b8e7cb457' 
  AND token = 'AIOiBOxnwzpyavnS9EAXjKfv1HKPL10NpPqplVryLoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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