SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6bb40467c0d773df6d50542108e637f432a915f8f51ef68c47df85099141c8b' 
  AND token = 'jrxYaGWycslFz7SWrZak8n8wccg2+MVzFSD5BD78gVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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