SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dab4f0ce99f81cbc4c136be6018e7656940cf952ec7fa475e4cd3cd4a5b19afd' 
  AND token = '5JjLslUrNgjhYCzuvW1TrBy3bM1SK+5XEG3HRRZM36I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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