SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c638c530ae0a81ef06a1a389fd45f9e7e64165b999b1f102b1bb777b6545cbd' 
  AND token = 'pcC8EXpTfQ5Qmyx5zcFyDLBnRCvm+GFKqDw7j643KtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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