SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b701119847a6209e15e5bcc97475da05e327a58e21e4468bc5bd6e2aaad302b' 
  AND token = '0V6aPgIcnS5ApVG5XVK5ng1FC5BO/ilxgzpdjz5RUh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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