SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a877f92d310f8c3fd48b1f80964fb1cd2fac0743b8f440f815a10c0a769ec66e' 
  AND token = 'CH/SD/1JY4xuovmqS+UITIrYadyPqEsyEn390xGewH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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