SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c963b009971fdfd1de6f5cfb5c4cd3bb97b5bd8d49a0fa503064aa28e2140d7' 
  AND token = 'oLC2s4RnqBhz9ZAOqKRTbBECKuFPntO5zvdYQpYbYkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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