SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d292c020176006a15883e94bf174027dff238b431f5172b8e3926ca0d7d568a' 
  AND token = 'wEdz8CdClxxPedrmymTgPMKtrXwQKrF9jvzW+q6GyHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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