SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e1da10c445885357a60aeece7b42128261e88c8380a5110f059c23e8eefce06' 
  AND token = '/QSFMpeJZy8/PwosAKpP0eC8FwvzBloc8XfMiQzhoYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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