SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc794fa11a392c36a421249f6fdd0459c2bace644e51eb45ca7380c90a11148b' 
  AND token = 'nOqFygVzZPrKtshAj8sB3H68y/IC9JmhS3GUc/BGMAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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