SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '557a610ab13044a8aa2e73b95e8fab4733180714f908ee781706516d39fde593' 
  AND token = 'PcVwNugKvzGk3yORf3BjvxIkSa1PvFToB8N8/AljBwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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