SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fe5316abfc0f44e1414b88785c796180c47b22e22d7e4e705a84228c300e282' 
  AND token = 'ma3BQ5rtQp4gHfNuOYQKGdX7SXS/IoRHM0holnZl3JY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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