SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28f14a009f8d27eb81338eda950d672c28708b9aadf44df8b1a9f431ea59ef63' 
  AND token = 'iKhN0VLOiS26bQZZA/LQmnDPDYdkn+vBKzeu7BW34i8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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