SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acb2a334b248229c09e2744b201caeb161ea3feca05741fde108b1358ca9ff97' 
  AND token = 'K5q4OeFB1B2NhT7MjOcGXzPIfFcRblACmQtDxJNs4vE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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