SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96710dc1e30460b46f67a7b17fbf7fefc75b51886092bf989bc22ff8d78a2766' 
  AND token = 'MXzFrAL97I9Z9mWoFn+NXZndIzAzlGqagL46URVg6pA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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