SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5672d14e66a9f7ff939cfc0aed1122ca6ae2ff3aa848370f13da6db21f704912' 
  AND token = 'wDlUKO2yjgzvX6jeyPHIAE2azIsijHBXVUJxk/dfsTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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