SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d0290a63d9059a8261d4aad41e071cc7a323dadf65eaeb6e9bedd7d305aca18' 
  AND token = 'fUbKaX27duSZwe3GAbvTbF58FVJEtXQZMQycvYc3UxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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