SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67afe1e0d1e7b3e3a293a7e1168b8b8aa3387ffc316037ad6ba16dcff9650bf6' 
  AND token = 'jKtGo8HD7Wz4BYKCuwV7n8TFsBqQidoKhH8eCxgg/FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}