SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef374bd0003ba45efeee381141cb790727ae3c19202995dc83906ba70d2d2369' 
  AND token = 'iNVDtWk0l37D+EiBXp/IuPfdssmMHaAaHpuLTBxyZBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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