SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d3f07858742d4aca0891afe4791cce058dbb426962d162e7c98fe6d3a39e403' 
  AND token = 'K8LM8RqXJI5m3MOND6wBnSc9NDGhuN4Syy47CNKCGII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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