SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42f3fd488f3a8e52adbc4cbf7cb31f52b4d2dca8d5a88ff8b223165b7bfafafe' 
  AND token = '7MLf9J68wB2ESbUUDzy8usnDVxbihnJBq0lfqmEjJ/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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