SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28c2ab841a188bae6ba3e8fac697bff26c79076026953cbb4bda1cbf13a10ef0' 
  AND token = 'Vm/qhK8jAVCrg3MsRTWcPZijaJl5RMECZpJGHQK/e2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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