SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de90b718a8e3adf24584ed76dfca7ab524dc488bfd36a73afd8989a17aafbe21' 
  AND token = 'ZJn1gvYXBYKtG81wXwJh4qp5HIENp9UCFRHTJ7S4XuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}