SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c3b5addc2776bc4341e94ff60cd21f64f08bee889b2e72052a7c9c3a286954a' 
  AND token = 'VQ6Os0Op9qN+rnXIyI7JRLFZcxwYxexvSK7tjfQWqMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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