SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad502f6d5b89fb5a8a3fc91efe95c951d3c6852d69141acd70fb249e8c4f0565' 
  AND token = 'XZDBDCbbCPI1zv4fIIHYZO+RHzKAgGEw1eJ/+9KSqpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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