SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5d9a9276f84cebfc48c7135d67b355f68ec4dc967862f90f3dacb452e7ae729' 
  AND token = 'Udq6pKLq9afPY5opkTiK6jYI6FGU04sbqxURTM4HKaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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