SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c44cc1729457b436bfe9e7d65f72ece4b8fc339b0af78cb8cae27bed0e7fb5cc' 
  AND token = '4ClrwI3pdGL4zqMEoOoLaIFhj2NkeAaWfLNTeH3MiV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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