SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac9c397d83704b429b0e3364472a2e1141a5d89835368b9e6ecfa29e5ff6beb1' 
  AND token = '3fhJwjXtT2A5wKFVN/3BqjnOGo6V9ui5EMyqg8hyGiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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